RFR: 8337143: (fc, fs) Move filesystem-related native objects from libnio to libjava [v4]

[Brian Burkhalter]

> This proposed change would move the native objects required for NIO file interaction from the libnio native library to the libjava native library on Linux, macOS, and Windows.

Brian Burkhalter 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 four additional commits since the last revision:

 - Merge
 - 8337143: Removed dependency of libjava on headers in libnio/ch
 - 8337143: Move natives to <platform>/native/libjava/nio/{ch,fs} as a function of their original location in libnio
 - 8337143: (fc, fs) Move filesystem-related native objects from libnio to libjava

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Changes:
  - all: https://git.openjdk.org/jdk/pull/20317/files
  - new: https://git.openjdk.org/jdk/pull/20317/files/7e8a02e3..e28a4f57

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=20317&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=20317&range=02-03

  Stats: 23454 lines in 774 files changed: 12481 ins; 7665 del; 3308 mod
  Patch: https://git.openjdk.org/jdk/pull/20317.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20317/head:pull/20317

PR: https://git.openjdk.org/jdk/pull/20317