RFR: 8342206: Convenience method to check if a ClassEntry matches a ClassDesc [v2]

[Chen Liang]

> Currently, to efficiently check if a `ClassEntry`, such as one from an `InvokeInstruction`, is of a particular class, we use such a pattern (as seen in JEP 486 [Appendix](https://openjdk.org/jeps/486#Appendix)):
> 
> inst.owner().name().equalsString("java/lang/System")
> 
> This pattern has a few issues:
> 
> 1. This is not straightforward. Users may be tempted to write
> 
> inst.owner().asSymbol().equals(CD_System)
> 
> unaware of the degraded performance from extra conversions.
> 
> 2. We aim to reduce the use of "internal names" with encapsulation. Direct use of `"java/lang/System"` goes against this, and we have no constants offered to reduce such error-prone use of internal name.
> 
> Thus, I propose a new API in `ClassEntry`:
> 
> boolean equalsSymbol(ClassDesc)
> 
> that can be used conveniently to check the identity of a class entry with a clean syntax and better performance.

Chen Liang has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:

 - Reuse cache for arrays, replace some use cases
 - Merge branch 'master' of https://github.com/openjdk/jdk into feature/classentry-equalssym
 - 8342206: Convenience method to check if a ClassEntry matches a ClassDesc

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/21526/files
  - new: https://git.openjdk.org/jdk/pull/21526/files/c6e40fd9..54139eae

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=21526&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=21526&range=00-01

  Stats: 9095 lines in 179 files changed: 6849 ins; 690 del; 1556 mod
  Patch: https://git.openjdk.org/jdk/pull/21526.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21526/head:pull/21526

PR: https://git.openjdk.org/jdk/pull/21526