RFR: 8338544: Dedicated Array class descriptor implementation [v7]

[Chen Liang]

> @cl4es discovered that Stack Map generation in ClassFile API uses `componentType` and `arrayType` for `aaload` `aastore` instructions, which are currently quite slow. We can split out array class descriptors from class or interfaces to support faster `arrayType` and `componentType` operations.
> 
> Tentative, as I currently have no way to measure the actual impact of this patch on the startup performance; however, this made the `ClassDesc` implementations much cleaner.

Chen Liang has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 19 commits:

 - Merge branch 'master' of https://github.com/openjdk/jdk into feature/array-cd
 - Restore the impl spec to the API spec
 - Relax displayName spec
 - Merge branch 'master' of https://github.com/openjdk/jdk into feature/array-cd
 - Merge
 - object array desc constant
 - Merge branch 'master' of https://github.com/openjdk/jdk into feature/array-cd
 - Mandy reviews
 - Merge branch 'master' of https://github.com/openjdk/jdk into feature/array-cd
 - mlchung suggestions: elementType, improve utility methods
 - ... and 9 more: https://git.openjdk.org/jdk/compare/d6eddcda...bf9ff94c

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Changes: https://git.openjdk.org/jdk/pull/20665/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=20665&range=06
  Stats: 838 lines in 19 files changed: 445 ins; 255 del; 138 mod
  Patch: https://git.openjdk.org/jdk/pull/20665.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20665/head:pull/20665

PR: https://git.openjdk.org/jdk/pull/20665