RFR: 8264774: Implementation of Foreign Function and Memory API (Incubator) [v26]

[Maurizio Cimadamore]

> This PR contains the API and implementation changes for JEP-412 [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/412

Maurizio Cimadamore has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 37 commits:

 - Merge branch 'master' into JEP-412
 - * Add missing `final` in some static fields
   * Downgrade native methods in ProgrammableUpcallHandler to package-private
 - Add sealed modifiers in morally sealed API interfaces
 - Merge branch 'master' into JEP-412
 - Fix VaList test
   Remove unused code in Utils
 - Merge pull request #11 from JornVernee/JEP-412-MXCSR
   
   Add MXCSR save and restore to upcall stubs for non-windows platforms
 - Add MXCSR save and restore to upcall stubs for non-windows platforms
 - Merge branch 'master' into JEP-412
 - Fix issue with bounded arena allocator
 - Rename is_entry_blob to is_optimized_entry_blob
   Rename as_entry_blob to as_optimized_entry_blob
   Fix misc typos and indentation issues
 - ... and 27 more: https://git.openjdk.java.net/jdk/compare/7278f56b...8bbddfc2

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Changes: https://git.openjdk.java.net/jdk/pull/3699/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=3699&range=25
  Stats: 14501 lines in 219 files changed: 8847 ins; 3642 del; 2012 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3699.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3699/head:pull/3699

PR: https://git.openjdk.java.net/jdk/pull/3699