RFR: 8368050: Validation missing in ClassFile signature factories [v4]

[Chen Liang]

> The Signature modeling in the ClassFile API is missing some validations required by JVMS, notably identifier character restrictions and void type restrictions. In addition, the model currently uses `ClassDesc` to indicate a simple name for an inner class signature, which is incorrect, and this patch proposes to deprecate that API for removal.

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 five additional commits since the last revision:

 - Fix bad docs and add more to clarify class type sig
 - Merge branch 'master' of https://github.com/openjdk/jdk into fix/cf-classtypesig-factory-classdesc
 - Fix links
 - More bugs
 - 8368050: Validation missing in ClassFile signature factories

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Changes:
  - all: https://git.openjdk.org/jdk/pull/27380/files
  - new: https://git.openjdk.org/jdk/pull/27380/files/3acdfe4a..b21f811e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27380&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27380&range=02-03

  Stats: 6010 lines in 136 files changed: 4752 ins; 998 del; 260 mod
  Patch: https://git.openjdk.org/jdk/pull/27380.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27380/head:pull/27380

PR: https://git.openjdk.org/jdk/pull/27380