RFR: 8335091: NMT: VMATree reserve_mapping and commit_mapping APIs need ME…MFLAGS while un/-committing API has no MEMFLAGS arg

[Afshin Zafari]

An optional bool arg is added to copy the existing flag of the left node to the new nodes.

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Commit messages:
 - 8335091: NMT: VMATree reserve_mapping and commit_mapping APIs need MEMFLAGS while un/-committing API has no MEMFLAGS arg

Changes: https://git.openjdk.org/jdk/pull/20330/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=20330&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8335091
  Stats: 30 lines in 3 files changed: 24 ins; 0 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/20330.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20330/head:pull/20330

PR: https://git.openjdk.org/jdk/pull/20330