[foreign-jextract] RFR: Improve NIO channel support for buffer views over segments [v2]

[Chris Hegarty]

> Initial prototype changes to use resource scope handles when performing I/O operations with synchronous and asynchronous channels.

Chris Hegarty 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 six additional commits since the last revision:

 - Apply new acquire/release semantics, and remove AutoCloseable from HandleImpl
 - Fix Windows issues
 - Merge branch 'foreign-memaccess+abi' into buffers+resourceScope_Lock
 - remove explicit checkValidState check
 - Remove unnecessary abstract override
 - Prototype 2 Initial load

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Changes:
  - all: https://git.openjdk.java.net/panama-foreign/pull/512/files
  - new: https://git.openjdk.java.net/panama-foreign/pull/512/files/60d491c2..a88ad97a

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=panama-foreign&pr=512&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=panama-foreign&pr=512&range=00-01

  Stats: 754 lines in 30 files changed: 531 ins; 78 del; 145 mod
  Patch: https://git.openjdk.java.net/panama-foreign/pull/512.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-foreign pull/512/head:pull/512

PR: https://git.openjdk.java.net/panama-foreign/pull/512