Add the latest e2e-tests updates to upcoming notes

Based on the significant updates to that core framework since every
previous release. Use the same text for every upcoming release notes.

Add these updates also to the upcoming, more major 3.2 release notes.
Do so for main release content clarity and comprehensiveness purposes.

Beside the updated core notes, name the few plugins for which e2e tests
were also changed, correspondingly. This is to help readers understand
the scope of each framework update.

Change-Id: I7146384a24a92206d6efabc169524f79d4c41b85
diff --git a/pages/site/releases/2.16.md b/pages/site/releases/2.16.md
index f1f3eab..7131b82 100644
--- a/pages/site/releases/2.16.md
+++ b/pages/site/releases/2.16.md
@@ -639,6 +639,36 @@
 
   * Add support for Elasticsearch 7.7.
 
+* End-to-end Tests Improvements
+
+  * Allow end-to-end tests to proportionally scale on their expected execution times.
+
+    A `power_factor` [environment property](https://gerrit-review.googlesource.com/Documentation/dev-e2e-tests.html#_environment_properties)
+    was added to the end-to-end tests core framework. Using that optional property,
+    scenario steps can take some more (or less) time prior to expecting proper completion.
+
+    The way to set that property locally then depends on the target runtime environment,
+    or SUT latency. The property may be used for either core or plugin scenarios.
+
+  * `FlushProjectsCache` related scenarios added to core (and the `high-availability` plugin).
+
+  * Support for relative runtime weights in scenarios.
+
+    Each scenario can now either weight like any other by default, or override that default
+    with a greater weight value, compared to siblings that are lighter on execution times.
+
+    Beside core, make the `high-availability` and `multi-site` plugin scenarios reuse this.
+
+  * Allow scenarios to create and delete Gerrit changes alongside projects.
+
+    Add the corresponding core support for an optional `http` request body to every such
+    `GerritSimulation`. Either automate or allow [environment properties](https://gerrit-review.googlesource.com/Documentation/dev-e2e-tests.html#_environment_properties)
+    to feed the related input test data.
+
+    Beside core, make the `high-availability` and `multi-site` plugin scenarios test changes
+    that way. The latter currently has [Issue 12693](https://bugs.chromium.org/p/gerrit/issues/detail?id=12693)
+    as a known limitation.
+
 * Bug Fixes
 
   * [Issue 12637](https://bugs.chromium.org/p/gerrit/issues/detail?id=12637):
diff --git a/pages/site/releases/3.0.md b/pages/site/releases/3.0.md
index c56fe31..04e1105 100644
--- a/pages/site/releases/3.0.md
+++ b/pages/site/releases/3.0.md
@@ -209,6 +209,36 @@
   * [Issue 12527](https://bugs.chromium.org/p/gerrit/issues/detail?id=12527):
   Elasticsearch: Support for EOL versions v5.6 and v6.0 to v6.5 is discontinued
 
+* End-to-end Tests Improvements
+
+  * Allow end-to-end tests to proportionally scale on their expected execution times.
+
+    A `power_factor` [environment property](https://gerrit-review.googlesource.com/Documentation/dev-e2e-tests.html#_environment_properties)
+    was added to the end-to-end tests core framework. Using that optional property,
+    scenario steps can take some more (or less) time prior to expecting proper completion.
+
+    The way to set that property locally then depends on the target runtime environment,
+    or SUT latency. The property may be used for either core or plugin scenarios.
+
+  * `FlushProjectsCache` related scenarios added to core (and the `high-availability` plugin).
+
+  * Support for relative runtime weights in scenarios.
+
+    Each scenario can now either weight like any other by default, or override that default
+    with a greater weight value, compared to siblings that are lighter on execution times.
+
+    Beside core, make the `high-availability` and `multi-site` plugin scenarios reuse this.
+
+  * Allow scenarios to create and delete Gerrit changes alongside projects.
+
+    Add the corresponding core support for an optional `http` request body to every such
+    `GerritSimulation`. Either automate or allow [environment properties](https://gerrit-review.googlesource.com/Documentation/dev-e2e-tests.html#_environment_properties)
+    to feed the related input test data.
+
+    Beside core, make the `high-availability` and `multi-site` plugin scenarios test changes
+    that way. The latter currently has [Issue 12693](https://bugs.chromium.org/p/gerrit/issues/detail?id=12693)
+    as a known limitation.
+
 ### 3.0.8
 
 * Breaking Changes
diff --git a/pages/site/releases/3.1.md b/pages/site/releases/3.1.md
index c954ed2..06aa3f8 100644
--- a/pages/site/releases/3.1.md
+++ b/pages/site/releases/3.1.md
@@ -309,6 +309,36 @@
   * [Issue 12527](https://bugs.chromium.org/p/gerrit/issues/detail?id=12527):
   Elasticsearch: Support for EOL versions v5.6 and v6.0 to v6.5 is discontinued
 
+* End-to-end Tests Improvements
+
+  * Allow end-to-end tests to proportionally scale on their expected execution times.
+
+    A `power_factor` [environment property](https://gerrit-review.googlesource.com/Documentation/dev-e2e-tests.html#_environment_properties)
+    was added to the end-to-end tests core framework. Using that optional property,
+    scenario steps can take some more (or less) time prior to expecting proper completion.
+
+    The way to set that property locally then depends on the target runtime environment,
+    or SUT latency. The property may be used for either core or plugin scenarios.
+
+  * `FlushProjectsCache` related scenarios added to core (and the `high-availability` plugin).
+
+  * Support for relative runtime weights in scenarios.
+
+    Each scenario can now either weight like any other by default, or override that default
+    with a greater weight value, compared to siblings that are lighter on execution times.
+
+    Beside core, make the `high-availability` and `multi-site` plugin scenarios reuse this.
+
+  * Allow scenarios to create and delete Gerrit changes alongside projects.
+
+    Add the corresponding core support for an optional `http` request body to every such
+    `GerritSimulation`. Either automate or allow [environment properties](https://gerrit-review.googlesource.com/Documentation/dev-e2e-tests.html#_environment_properties)
+    to feed the related input test data.
+
+    Beside core, make the `high-availability` and `multi-site` plugin scenarios test changes
+    that way. The latter currently has [Issue 12693](https://bugs.chromium.org/p/gerrit/issues/detail?id=12693)
+    as a known limitation.
+
 ### 3.1.4
 
 * Breaking Changes
diff --git a/pages/site/releases/3.2.md b/pages/site/releases/3.2.md
index a2ece17..aae388a 100644
--- a/pages/site/releases/3.2.md
+++ b/pages/site/releases/3.2.md
@@ -157,6 +157,36 @@
   Allow developers who are not familiar with the idiosyncrasies of repo,
   to easily create a local branch when checking out changes.
 
+### End-to-end tests
+
+* Allow end-to-end tests to proportionally scale on their expected execution times.
+
+  A `power_factor` [environment property](https://gerrit-review.googlesource.com/Documentation/dev-e2e-tests.html#_environment_properties)
+  was added to the end-to-end tests core framework. Using that optional property,
+  scenario steps can take some more (or less) time prior to expecting proper completion.
+
+  The way to set that property locally then depends on the target runtime environment,
+  or SUT latency. The property may be used for either core or plugin scenarios.
+
+* `FlushProjectsCache` related scenarios added to core (and the `high-availability` plugin).
+
+* Support for relative runtime weights in scenarios.
+
+  Each scenario can now either weight like any other by default, or override that default
+  with a greater weight value, compared to siblings that are lighter on execution times.
+
+  Beside core, make the `high-availability` and `multi-site` plugin scenarios reuse this.
+
+* Allow scenarios to create and delete Gerrit changes alongside projects.
+
+  Add the corresponding core support for an optional `http` request body to every such
+  `GerritSimulation`. Either automate or allow [environment properties](https://gerrit-review.googlesource.com/Documentation/dev-e2e-tests.html#_environment_properties)
+  to feed the related input test data.
+
+  Beside core, make the `high-availability` and `multi-site` plugin scenarios test changes
+  that way. The latter currently has [Issue 12693](https://bugs.chromium.org/p/gerrit/issues/detail?id=12693)
+  as a known limitation.
+
 ## Bug Fixes
 
 * Replication plugin fixes