RFR: 8297209: Serial: Refactor GenCollectedHeap::full_process_roots [v2]

[Albert Mingkun Yang]

> Simple change of replacing `MarkingCodeBlobClosure` with `CodeBlobToOopClosure` in the adjust-phase of Full GC.
> 
> Test: tier1-5

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/11210/files
  - new: https://git.openjdk.org/jdk/pull/11210/files/e54568c6..3e6cdb36

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=11210&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=11210&range=00-01

  Stats: 44 lines in 3 files changed: 10 ins; 26 del; 8 mod
  Patch: https://git.openjdk.org/jdk/pull/11210.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11210/head:pull/11210

PR: https://git.openjdk.org/jdk/pull/11210