RFR: 8295044: Implementation of Foreign Function and Memory API (Second Preview) [v38]

[Maurizio Cimadamore]

> This PR contains the API and implementation changes for JEP-434 [1]. A more detailed description of such changes, to avoid repetitions during the review process, is included as a separate comment.
> 
> [1] - https://openjdk.org/jeps/434

Maurizio Cimadamore has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 70 commits:

 - Merge branch 'master' into PR_20
 - Address review comments
 - Address review comments
 - Merge branch 'master' into PR_20
 - Address review comment
 - Polish javadoc:
   * Make sure that first para of class javadoc is succinct and descriptive
   * Remove references to "access" var handle or "memory segment view" var handle (just use var handle)
   * Minor tweak to layout classes javadoc - use `@see` in value layouts instead of a dedicated para.
   * Other minor typos fixes
 - Address review comments
 - * remove unused Scoped interface
   * re-add trusting of final fields in layout class implementations
   * Fix BulkOps benchmark, which had alignment issues
 - Fix bit vs. byte mismatch in test
 - Fix wrong check in MemorySegment::spliterator/elements
   (The check which ensures that the segment size is multiple of spliterator element size is bogus)
 - ... and 60 more: https://git.openjdk.org/jdk/compare/4485d4e5...8b5dc0f0

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Changes: https://git.openjdk.org/jdk/pull/10872/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10872&range=37
  Stats: 13807 lines in 254 files changed: 5780 ins; 4448 del; 3579 mod
  Patch: https://git.openjdk.org/jdk/pull/10872.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10872/head:pull/10872

PR: https://git.openjdk.org/jdk/pull/10872