RFR: 8282191: Implementation of Foreign Function & Memory API (Preview) [v31]

[Maurizio Cimadamore]

> This PR contains the API and implementation changes for JEP-424 [1]. A more detailed description of such changes, to avoid repetitions during the review process, is included as a separate comment.
> 
> [1] - https://openjdk.java.net/jeps/424

Maurizio Cimadamore has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 50 commits:

 - Merge branch 'master' into foreign-preview
 - Add ValueLayout changes
 - Tweak support for array element var handle
 - Add @see
 - Initial push
 - Remove whitespaces
 - Drop `UnsupportedOperationException` from throws clause in FileChannel/FileChannelImpl
 - Add @ForceInline annotation on session accessor
   Beef up UnrolledAccess benchmark
 - Use a less expensive array element alignment check
   The bit to byte conversion shows up in hot paths
 - Fix UnrolledAccess benchmark
 - ... and 40 more: https://git.openjdk.java.net/jdk/compare/72f82dd7...746de5ce

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Changes: https://git.openjdk.java.net/jdk/pull/7888/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=7888&range=30
  Stats: 65314 lines in 367 files changed: 43344 ins; 19432 del; 2538 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7888.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7888/head:pull/7888

PR: https://git.openjdk.java.net/jdk/pull/7888