RFR: 8310683: Refactor StandardCharset/standard.java to use JUnit [v3]

[Justin Lu]

> Please review this PR which is apart of the migration of JDK tests to JUnit. Standard.java is refactored to use JUnit, and thus split up into the following tests.
> 
> - typeTest
> - nameMethodTest
> - forNameMethodTest
> - charsetModifiersTest
> - correctCharsetsTest
> 
>  Additionally all unused methods were removed.

Justin Lu has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 19 commits:

 - Merge pr/14599
 - Additional cleanup
 - Refactor Standard.java to use JUnit + other cleanup
 - Fix imports and update copyright year
 - 8309685: Fix -Wconversion warnings in assembler and register code
   
   Reviewed-by: aph, fparain
 - 8310618: Test serviceability/sa/ClhsdbDumpclass.java fails after 8242152: 'StackMapTable:' missing from stdout/stderr
   
   Reviewed-by: kevinw, dholmes
 - 8310591: Missing `@since` tags in java.lang.foreign
   
   Reviewed-by: mcimadamore
 - 8310561: JFR: Unify decodeDescriptors(String, String)
   
   Reviewed-by: mgronlun
 - 8310549: avoid potential leaks in KeystoreImpl.m related to JNU_CHECK_EXCEPTION early returns
   
   Reviewed-by: weijun
 - 8242152: SA does not include StackMapTables when dumping .class files
   
   Reviewed-by: cjplummer, sspitsyn
 - ... and 9 more: https://git.openjdk.org/jdk/compare/0eb1df40...fbd49394

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

Changes: https://git.openjdk.org/jdk/pull/14621/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=14621&range=02
  Stats: 477 lines in 44 files changed: 175 ins; 80 del; 222 mod
  Patch: https://git.openjdk.org/jdk/pull/14621.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14621/head:pull/14621

PR: https://git.openjdk.org/jdk/pull/14621