RFR: 8366660: Sort share/nmt includes

[Francesco Andreuzzi]

Sort include statements in `hotspot/share/nmt` using `SortIncludes.java`. I'm also removing a couple unnecessary includes.

Passes `tier1`.

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Commit messages:
 - sort

Changes: https://git.openjdk.org/jdk/pull/27042/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27042&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8366660
  Stats: 34 lines in 15 files changed: 18 ins; 15 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/27042.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27042/head:pull/27042

PR: https://git.openjdk.org/jdk/pull/27042