RFR: 8337143: (fc, fs) Move filesystem-related native objects from libnio to libjava [v6]

[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 pull request now contains six commits:

 - Merge
 - 8337143: Remove loading libnet from Inet6AddressImpl; delete commented out #include in Windows IOUtil.c
 - 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

-------------

Changes: https://git.openjdk.org/jdk/pull/20317/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=20317&range=05
  Stats: 1561 lines in 90 files changed: 771 ins; 674 del; 116 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