RFR: 8378700: Migrate lang/annotation tests away from TestNG [v2]

[Chen Liang]

> Remove the use of TestNG from java/lang/annotation tests.
> Interesting that JUnit scans annotations on member classes, so we can't put malformed annotations on classes nested in the test class; we can put them on package-private classes in the same source file instead.
> Also refactored LoaderLeakTest to perform GC more reliably within our test framework.

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

  Update test/jdk/java/lang/annotation/typeAnnotations/TestExecutableGetAnnotatedType.java
  
  Co-authored-by: Andrey Turbanov <turbanoff at gmail.com>

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Changes:
  - all: https://git.openjdk.org/jdk/pull/29921/files
  - new: https://git.openjdk.org/jdk/pull/29921/files/cad3d2ea..e4bdf341

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=29921&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=29921&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/29921.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29921/head:pull/29921

PR: https://git.openjdk.org/jdk/pull/29921