RFR: 8284871: Use covariant overrides for the resolveConstantDesc(Lookup) method in sub‑interfaces of java.lang.constant.ConstantDesc [v3]

[Chen Liang]

> Also remove redundant casts to avoid javac warnings.

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 eight additional commits since the last revision:

 - Retain a general note in ConstantDesc
 - Merge branch 'master' into constdesc-override
 - Update tests to remove useless casts and update copyright year
 - Merge branch 'master' into constdesc-override
 - Move MethodTypeDesc api notes to MethodTypeDesc
 - Merge branch 'master' of https://git.openjdk.java.net/jdk into constdesc-override
 - Remove redundant casts
 - Covariant override of resolveConstantDesc for Class/MethodType/MethodHandleDesc

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Changes:
  - all: https://git.openjdk.org/jdk/pull/12986/files
  - new: https://git.openjdk.org/jdk/pull/12986/files/5b26556d..23670070

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=12986&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=12986&range=01-02

  Stats: 12267 lines in 279 files changed: 4215 ins; 7423 del; 629 mod
  Patch: https://git.openjdk.org/jdk/pull/12986.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/12986/head:pull/12986

PR: https://git.openjdk.org/jdk/pull/12986