RFR: 8343742: Test TestShenandoah.java fails Could not find leaking object [v2]

[SendaoYan]

> Hi all,
>  Test `jdk/jfr/event/oldobject/TestShenandoah.java` run timed out after [JDK-8279016](https://bugs.openjdk.org/browse/JDK-8279016), because of infinite loop of `Could not find leaking object, retrying...`
> In [JDK-8279016](https://bugs.openjdk.org/browse/JDK-8279016), this test has been Problemlisted by [ProblemList-shenandoah.txt
> ](https://github.com/openjdk/jdk/blame/master/test/jdk/ProblemList-shenandoah.txt#L52), because of the LeakProfiler tests not suitable for run with `-XX:+UseShenandoahGC` after [JDK-8279016](https://bugs.openjdk.org/browse/JDK-8279016).
> But in the VM option `-XX:+UseShenandoahGC` set inside the test tag cause the Problemlist mechanism will not take effect. The problemlist only take effect when the VM option set from command line such as `make TEST JTREG="JAVA_OPTIONS=-XX:+UseShenandoahGC"`.
> So in this PR move Problemlist entry `jdk/jfr/event/oldobject/TestShenandoah.java` from `test/jdk/ProblemList-shenandoah.txt` to `test/jdk/ProblemList.txt` to make this test could by excluded normally.
> The other optional solution is delete the VM option `-XX:+UseShenandoahGC` in test file to make test run passed. After [JDK-8342951](https://bugs.openjdk.org/browse/JDK-8342951) has been resolved, the change should be backouted. This PR choice the previous one solution.
> 
> Test-fix only, no risk.

SendaoYan has updated the pull request incrementally with one additional commit since the last revision:

  Move Problemlist entry jdk/jfr/event/oldobject/TestShenandoah.java from test/jdk/ProblemList-shenandoah.txt to test/jdk/ProblemList.txt

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/21951/files
  - new: https://git.openjdk.org/jdk/pull/21951/files/f54ed654..30a73e8a

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=21951&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=21951&range=00-01

  Stats: 4 lines in 3 files changed: 1 ins; 1 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/21951.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21951/head:pull/21951

PR: https://git.openjdk.org/jdk/pull/21951