RFR: 8366241: NMT: Consolidate [Virtual/Committed/Reserved]Regions into one structure [v5]

[Afshin Zafari]

> The structures `CommittedMemoryRegion` and `ReservedMemoryRegion` are merged into the `VirtualMemoryRegion`.
> 
> Tests:
> tiers1-5, main platforms, debug/product

Afshin Zafari has updated the pull request incrementally with one additional commit since the last revision:

  fixes

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/27137/files
  - new: https://git.openjdk.org/jdk/pull/27137/files/ec846aa4..1f29d6a4

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27137&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27137&range=03-04

  Stats: 17 lines in 1 file changed: 1 ins; 13 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/27137.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27137/head:pull/27137

PR: https://git.openjdk.org/jdk/pull/27137