RFR: 8310843: Reimplement ByteArray and ByteArrayLittleEndian with Unsafe [v10]

[Glavo]

> `ByteArray` and `ByteArrayLittleEndian` are very useful tool classes that can be used in many places to performance tuning.
> 
> Currently they are implemented by `VarHandle`, so using them may have some impact on startup time.
> 
> This PR reimplements them using `Unsafe`, which reduces the impact on startup time.

Glavo 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 15 additional commits since the last revision:

 - Merge branch 'openjdk:master' into unsafe
 - add 8310843 to @bug
 - Merge branch 'openjdk:master' into unsafe
 - Merge branch 'openjdk:master' into unsafe
 - delete incorrect comments
 - delete extraneous whitespace
 - add javadoc
 - delete extraneous whitespace
 - fix test
 - update tests
 - ... and 5 more: https://git.openjdk.org/jdk/compare/c32a834b...cb56e736

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/14636/files
  - new: https://git.openjdk.org/jdk/pull/14636/files/7cfef770..cb56e736

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=14636&range=09
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=14636&range=08-09

  Stats: 66403 lines in 1073 files changed: 14359 ins; 48801 del; 3243 mod
  Patch: https://git.openjdk.org/jdk/pull/14636.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14636/head:pull/14636

PR: https://git.openjdk.org/jdk/pull/14636