Bump Gerrit to v3.3.7 in docker-based tests

Update Gerrit version for E2E docker-based tests
and align the JavaMelody plugin URL for stable-3.3.

Change-Id: I159fcab777a78b0877aa2f6c21af278feacfe5a9

src/test/docker/gerrit/Dockerfile

diff --git a/src/test/docker/gerrit/Dockerfile b/src/test/docker/gerrit/Dockerfile
index 3c74b10..7269a3a 100644
--- a/src/test/docker/gerrit/Dockerfile
+++ b/src/test/docker/gerrit/Dockerfile
@@ -1,6 +1,6 @@
-FROM gerritcodereview/gerrit:3.2.10
+FROM gerritcodereview/gerrit:3.3.7 
 
-ENV GERRIT_BRANCH=stable-3.2
+ENV GERRIT_BRANCH=stable-3.3
 
 ENV GERRIT_CI_URL=https://gerrit-ci.gerritforge.com/job
 
@@ -10,7 +10,7 @@
 
 USER gerrit
 
-ADD --chown=gerrit:gerrit $GERRIT_CI_URL/plugin-javamelody-bazel-$GERRIT_BRANCH/lastSuccessfulBuild/artifact/bazel-bin/plugins/javamelody/javamelody.jar /var/gerrit/plugins/javamelody.jar
+ADD --chown=gerrit:gerrit $GERRIT_CI_URL/plugin-javamelody-bazel-master-$GERRIT_BRANCH/lastSuccessfulBuild/artifact/bazel-bin/plugins/javamelody/javamelody.jar /var/gerrit/plugins/javamelody.jar
 ADD --chown=gerrit:gerrit $GERRIT_CI_URL/plugin-high-availability-bazel-$GERRIT_BRANCH/lastSuccessfulBuild/artifact/bazel-bin/plugins/high-availability/high-availability.jar /var/gerrit/plugins/high-availability.jar
 
 USER root