RFR: 8351661: NMT: VMATree should support separate call-stacks for reserve and commit operations

[Afshin Zafari]

In NMT detail mode, we need to have separate call-stacks for Reserve and Commit operations.
This PR adds a second stack to every node that will be used when committing (and uncommitting) the start node of a reserved region.

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Commit messages:
 - 8351661: NMT: VMATree should support separate call-stacks for reserve and commit operations

Changes: https://git.openjdk.org/jdk/pull/24028/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24028&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8351661
  Stats: 81 lines in 4 files changed: 58 ins; 3 del; 20 mod
  Patch: https://git.openjdk.org/jdk/pull/24028.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24028/head:pull/24028

PR: https://git.openjdk.org/jdk/pull/24028