e2e-tests: Stabilize the ReplayRecordsFromFeeder scenario

Set the number of repetitions to the maximum order of magnitude that
works locally. Setting that number to >10 led to locally crashing with
exception traces. Using higher numbers mostly led to no Gatling report
generated or failure to generate it (out of exceptions). Replacing
'repeat' with 'forever' led to reaching a crashing state as well.

Remove the pull and push commands from the scenario. Either one of these
in led to more Gatling KOs than OKs; often only KOs were obtained (red).

Basically stabilize that scenario, until further scenarios using git
pull, push and/or more load can be steadily developed. Goal being, to
be able to reproduce successful executions of such introductory core
scenarios. External harnessing, if any, is to be included just as well.

The exception below can still often be seen when running this test
locally, but it doesn't prevent the scenario from reporting OKs (green).

[JGit-WorkQueue] ERROR o.e.j.internal.storage.file.LockFile
- Unlocking LockFile '/tmp/gatling-1586283237616/609/
  loadtest-repo-worktree/.git/gc.log.lock' failed
java.io.IOException: Could not delete file
  /tmp/gatling-1586283237616/609/loadtest-repo-worktree/.git/gc.log.lock
at org.eclipse.jgit.util.FileUtils.delete(FileUtils.java:219)
at org.eclipse.jgit.internal.storage.file.LockFile.unlock(LockFile.java:520)
at org.eclipse.jgit.internal.storage.file.GcLog.unlock(GcLog.java:143)
at org.eclipse.jgit.internal.storage.file.GC.lambda$0(GC.java:279)
(...)

Bug: Issue 12332
Change-Id: Ifb332276b9650ac7a4133f2fe35b9ae36c615c9d

e2e-tests/src/test/resources/data/com/google/gerrit/scenarios/ReplayRecordsFromFeeder.json

@@ -3,24 +3,8 @@
     "url": "ssh://admin@localhost:29418/loadtest-repo",
     "cmd": "clone"
   },
-  {
-    "url": "ssh://admin@localhost:29418/loadtest-repo",
-    "cmd": "pull"
-  },
-  {
-    "url": "ssh://admin@localhost:29418/loadtest-repo",
-    "cmd": "push"
-  },
   {
     "url": "http://localhost:8080/loadtest-repo",
     "cmd": "clone"
-  },
-  {
-    "url": "http://localhost:8080/loadtest-repo",
-    "cmd": "pull"
-  },
-  {
-    "url": "http://localhost:8080/loadtest-repo",
-    "cmd": "push"
   }
 ]