Merge branch 'stable-3.4' into stable-3.5
* stable-3.4:
Split integrations tests into separate Bazel targets.
Extract base test class for regular and async acceptance tests
Allow additional refs fallback to apply-objects
Stop creating redundant replication tasks from stream-events
Add event creation time to the apply object payload
Don't read git submodule commits during replication
Expose implicit dependency with the multi-site plugin
Ignore remote ref-updated stream events for replication
Increase test time to 900 seconds
Change-Id: I7b98c49d875e4f2917af21abec562a21582f6b28
