RFR: 8357165: test java/lang/invoke/ClassValueTest.java fails intermittently

[Chen Liang]

The test was originally written with product builds in mind; it didn't consider the slowness of debug builds, thus causing tests to fail.

Also there was a bug in testWeakAgainstClassValue: the test need to flush the backing map in the class to have the weak value removed. It is fixed in this patch as well.

Testing: ClassValueTest repeated 10 times on windows-x64/linux-x64/macosx-aarch64/linux-aarch64 fastdebug.

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Commit messages:
 - Restore incorrectly removed annotation
 - Fix problems with class value tests

Changes: https://git.openjdk.org/jdk/pull/25292/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=25292&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8357165
  Stats: 14 lines in 1 file changed: 5 ins; 6 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/25292.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25292/head:pull/25292

PR: https://git.openjdk.org/jdk/pull/25292