RFR: 8347840: Fix testlibrary compilation warnings

[Leonid Mesnik]

There few compiler warning disabled in the testlibary build.
They should be fixed or localized and removed from build to prevent new possible issues.

The main goal is to avoid new such issues in the testlibrary. 
Tested with tier1-5 to ensure that all tests were passed.

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Commit messages:
 - copyrights updates
 - dangling fixed
 - Merge branch 'master' of https://github.com/openjdk/jdk into warnings
 - restricted removed
 - cast removed
 - deprecation remove
 - try removed
 - preview reviewed
 - serial removed
 - rawtypes removed
 - ... and 2 more: https://git.openjdk.org/jdk/compare/a3be97e2...ae302c9c

Changes: https://git.openjdk.org/jdk/pull/23143/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23143&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8347840
  Stats: 86 lines in 30 files changed: 23 ins; 4 del; 59 mod
  Patch: https://git.openjdk.org/jdk/pull/23143.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23143/head:pull/23143

PR: https://git.openjdk.org/jdk/pull/23143