RFR: 8342659: Test vmTestbase/nsk/jdi/ObjectReference/referringObjects/referringObjects002/referringObjects002.java failed: Class nsk.share.jdi.TestClass1 was not unloaded [v2]

[Albert Mingkun Yang]

> Use `Reference.refersTo` API to get more up to date liveness info of a class after OOM is thrown. The approach of relying `Cleaner` thread can incur some "asynchronous" cause various retrying logic, complicating the flow.
> 
> The failure rate is ~60% before the fix and no failure for 2000 runs.
> 
> Test: tier1-5

Albert Mingkun Yang has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains four additional commits since the last revision:

 - Merge branch 'master' into test-unload
 - copyright
 - review
 - test-unload

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/27840/files
  - new: https://git.openjdk.org/jdk/pull/27840/files/36004136..49720706

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27840&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27840&range=00-01

  Stats: 2242 lines in 139 files changed: 1027 ins; 654 del; 561 mod
  Patch: https://git.openjdk.org/jdk/pull/27840.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27840/head:pull/27840

PR: https://git.openjdk.org/jdk/pull/27840