RFR: Merge openjdk/jdk:master

[William Kemper]

Sync up with upstream

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

Commit messages:
 - Merge branch 'shenandoah-master' into upstream-merge-test
 - Merge tag 'jdk-20+12' into upstream-merge-test
 - 8289764: gc/lock tests failed with "OutOfMemoryError: Java heap space: failed reallocation of scalar replaced objects"
 - 8292329: Enable CDS shared heap for zero builds
 - 8292739: Invalid legacy entries may be returned by Provider.getServices() call
 - 8290469: Add new positioning options to PassFailJFrame test framework
 - 8292679: Simplify thread creation in gtest and port 2 tests to new way
 - 8215916: The failure reason of an optional JAAS LoginModule is not logged
 - 8292816: GPL Classpath exception missing from assemblyprefix.h
 - 8292713: Unsafe.allocateInstance should be intrinsified without UseUnalignedAccesses
 - ... and 313 more: https://git.openjdk.org/shenandoah/compare/b4ff060b...ef4ddacf

The webrevs contain the adjustments done while merging with regards to each parent branch:
 - master: https://webrevs.openjdk.org/?repo=shenandoah&pr=161&range=00.0
 - openjdk/jdk:master: https://webrevs.openjdk.org/?repo=shenandoah&pr=161&range=00.1

Changes: https://git.openjdk.org/shenandoah/pull/161/files
  Stats: 71080 lines in 1430 files changed: 34589 ins; 29655 del; 6836 mod
  Patch: https://git.openjdk.org/shenandoah/pull/161.diff
  Fetch: git fetch https://git.openjdk.org/shenandoah pull/161/head:pull/161

PR: https://git.openjdk.org/shenandoah/pull/161