[jdk17u-dev] RFR: 8275582: Don't purge metaspace mapping lists [v2]

[Thomas Stuefe]

> I'd like to downport this, since it is a prerequisite for downporting [JDK-8275704](https://bugs.openjdk.org/browse/JDK-8275704)
> "Metaspace::contains() should be threadsafe".

Thomas Stuefe has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains two additional commits since the last revision:

 - Merge branch 'openjdk:master' into tstuefe-backport-3ff085e2
 - Backport 3ff085e2967508ad312c9d32fa908807aefe69ee

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

Changes:
  - all: https://git.openjdk.org/jdk17u-dev/pull/1048/files
  - new: https://git.openjdk.org/jdk17u-dev/pull/1048/files/48fd5780..3e4b1414

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=1048&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=1048&range=00-01

  Stats: 2922 lines in 71 files changed: 2124 ins; 162 del; 636 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/1048.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev pull/1048/head:pull/1048

PR: https://git.openjdk.org/jdk17u-dev/pull/1048