RFR: 8282191: Implementation of Foreign Function & Memory API (Preview) [v16]

[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 31 commits:

 - Merge branch 'master' into foreign-preview
 - Tweak FunctionDescriptor::argumentLayouts to return an immutable list
 - Fix bad usage of `@link` with primitive array types
 - Switch to daemon threads for async upcalls
 - Use thread local storage to optimize attach of async threads
 - Drop support for Constable from MemoryLayout/FunctionDescriptor
 - Merge branch 'master' into foreign-preview
 - Revert changes to RunTests.gmk
 - Add --enable-preview to micro benchmark java options
 - Address more review comments
 - ... and 21 more: https://git.openjdk.java.net/jdk/compare/ce27d9dd...247e5eb5

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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=15
  Stats: 64862 lines in 366 files changed: 43028 ins; 19321 del; 2513 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