RFR: 8323707: Adjust Classfile API's type arg model to better represent the embodied type

[Chen Liang]

API changes as discussed on the mailing list: https://mail.openjdk.org/pipermail/classfile-api-dev/2023-November/000419.html

Additional questions:
1. Whether to rename `WildcardIndicator.DEFAULT` to `NONE`

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Commit messages:
 - redundant line
 - Fix a test in langtools, copyright year
 - Merge branch 'master' of https://github.com/openjdk/jdk into fix/typearg-model
 - Implementation cleanup, test update
 - Merge branch 'master' into fix/typearg-model
 - Formatting
 - Nuke signatureString and fix test fialure from bad cast
 - Adjust the type arg model to better represent the embodied type

Changes: https://git.openjdk.org/jdk/pull/16517/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=16517&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8323707
  Stats: 130 lines in 6 files changed: 46 ins; 32 del; 52 mod
  Patch: https://git.openjdk.org/jdk/pull/16517.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16517/head:pull/16517

PR: https://git.openjdk.org/jdk/pull/16517