RFR: 8337217: Port VirtualMemoryTracker to use VMATree [v12]

[Afshin Zafari]

> - `VMATree` is used instead of `SortedLinkList` in new class `VirtualMemoryTrackerWithTree`.
>  -  A wrapper/helper `RegionTree` is made around VMATree to make some calls easier.
>  -  Both old and new versions exist in the code and can be selected via `MemTracker::set_version()`
>  - `find_reserved_region()` is used in 4 cases, it will be removed in further PRs.
>  - All tier1 tests pass except one ~that expects a 50% increase in committed memory but it does not happen~  https://bugs.openjdk.org/browse/JDK-8335167.
>  - Adding a runtime flag for selecting the old or new version can be added later.
>  - Some performance tests are added for new version, VMATree and Treap, to show the idea and should be improved later. Based on the results of comparing speed of VMATree and VMT, VMATree shows ~40x faster response time.

Afshin Zafari has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 55 commits:

 - Merge remote-tracking branch 'origin/master' into _8337217_nmt_VMT_with_tree
 - visit committed regions refined.
 - visit_committed_regions signature changed.
 - removed unused local var.
 - a missed change in a shenandoah file.
 - Merge remote-tracking branch 'origin/master' into _8337217_nmt_VMT_with_tree
 - some fixes.
 - Merge remote-tracking branch 'origin/master' into _8337217_nmt_VMT_with_tree
 - Roberto's feedback applied.
 - Merge remote-tracking branch 'origin/master' into _8337217_nmt_VMT_with_tree
 - ... and 45 more: https://git.openjdk.org/jdk/compare/b741f3fe...2afb8c79

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Changes: https://git.openjdk.org/jdk/pull/20425/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=20425&range=11
  Stats: 3042 lines in 47 files changed: 1264 ins; 1528 del; 250 mod
  Patch: https://git.openjdk.org/jdk/pull/20425.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20425/head:pull/20425

PR: https://git.openjdk.org/jdk/pull/20425