RFR: 8318447: Move NMT source code to own subdirectory [v3]

[Johan Sjölen]

> I think that NMT is deserving of its own subdirectory. Can we do a review of the changes before I fix the merge conflicts?
> 
> 1. Moved all the nmt source code from services/ to nmt/
> 2. Renamed all the include statements and sorted them
> 3. Fixed the include guards

Johan Sjölen has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains three commits:

 - Merge remote-tracking branch 'origin/master' into move-nmt
 - Fixed reviewed changes
 - Move NMT to its own subdirectory

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Changes: https://git.openjdk.org/jdk/pull/16276/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=16276&range=02
  Stats: 502 lines in 100 files changed: 211 ins; 210 del; 81 mod
  Patch: https://git.openjdk.org/jdk/pull/16276.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16276/head:pull/16276

PR: https://git.openjdk.org/jdk/pull/16276