RFR: 8317466: Enable interpreter oopMapCache for concurrent GCs

[Zhengyu Gu]

Interpreter oop maps are computed lazily during GC root scan and they are expensive to compute.

GCs uses a small hash table per instance class to cache computed oop maps during STW root scan, but not for concurrent root scan.

This patch is intended to enable `OopMapCache` for concurrent GCs.

Test:
  tier1 and tier2 fastdebug and release on MacOSX, Linux 86_84 and Linux 86_32.

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Commit messages:
 - Fix merge conflicts
 - Merge
 - cleanup
 - Merge branch 'master' into JDK-8317466
 - Cleanup
 - Merge branch 'master' into oopmapcache_for_concurrent_root_scan
 - v2
 - v1
 - v0
 - 8317240: Promptly free OopMapEntry after fail to insert the entry to OopMapCache

Changes: https://git.openjdk.org/jdk/pull/16074/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=16074&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8317466
  Stats: 56 lines in 10 files changed: 20 ins; 15 del; 21 mod
  Patch: https://git.openjdk.org/jdk/pull/16074.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16074/head:pull/16074

PR: https://git.openjdk.org/jdk/pull/16074