RFR: 8338546: Speed up ConstantPoolBuilder::classEntry(ClassDesc) [v5]

[Chen Liang]

> Speed up `ConstantPoolBuilder::classEntry(ClassDesc)` by going through `ClassDesc` comparison and reusing descriptor hash to calculate internal name hash if possible. No suitable device to run benchmarks so need to find something to run the new benchmark to ensure things work as intended.

Chen Liang has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 18 commits:

 - Merge branch 'master' of https://github.com/openjdk/jdk into feature/classentry-speedup
 - Fresh creation bench
 - Merge branch 'master' of https://github.com/openjdk/jdk into feature/classentry-speedup
 - Fix build
 - Merge branch 'master' of https://github.com/openjdk/jdk into feature/classentry-speedup
 - Buggy 2nd attempt - crashes hotspot
 - Merge branch 'master' of https://github.com/openjdk/jdk into feature/classentry-speedup
 - Merge branch 'master' of https://github.com/openjdk/jdk into feature/classentry-speedup
 - More conflicts
 - Merge branch 'master' of https://github.com/openjdk/jdk into feature/classentry-speedup
 - ... and 8 more: https://git.openjdk.org/jdk/compare/e97f0fe1...7f79042a

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Changes: https://git.openjdk.org/jdk/pull/20667/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=20667&range=04
  Stats: 689 lines in 7 files changed: 594 ins; 42 del; 53 mod
  Patch: https://git.openjdk.org/jdk/pull/20667.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20667/head:pull/20667

PR: https://git.openjdk.org/jdk/pull/20667