RFR: 8325259: Serial: Inline OldGenScanClosure during Young GC [v2]

[Albert Mingkun Yang]

> Simple inlining oop closure during card-scanning of young-gc.
> 
> Test: using the attached card-scanning-stressing benchmark, ~5x improvement (in terms of young-gc pause time) is observed on my box.

Albert Mingkun Yang has updated the pull request incrementally with one additional commit since the last revision:

  review

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Changes:
  - all: https://git.openjdk.org/jdk/pull/17711/files
  - new: https://git.openjdk.org/jdk/pull/17711/files/4db53022..0b90e68e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=17711&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=17711&range=00-01

  Stats: 8 lines in 5 files changed: 1 ins; 1 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/17711.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17711/head:pull/17711

PR: https://git.openjdk.org/jdk/pull/17711