RFR: 8354556: Expand value-based class warnings to java.lang.ref API

[Vicente Romero]

This PR is defining a new internal annotation, `@jdk.internal.RequiresIdentity`, with target types PARAMETER and TYPE_PARAMETER. The @RequiresIdentity annotation expresses the expectation that an argument to a given method or constructor parameter will be an object with a unique identity, not an instance of a value-based class; or that the type argument to a given type parameter will not be a value-based class type.

For more details please refer to the complete description in the corresponding JIRA entry [1]

TIA

[1] https://bugs.openjdk.org/browse/JDK-8354556

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Commit messages:
 - final adjustments
 - additional refactorings
 - removing unneeded changes
 - more refactorings
 - more refactorings and tests
 - refactoring
 - refactoring
 - covering more cases plus refactoring in order to simplify the code
 - Merge branch 'JDK-8354556' of https://github.com/vicente-romero-oracle/jdk into JDK-8354556
 - additional coverage for other uses of types
 - ... and 11 more: https://git.openjdk.org/jdk/compare/4dd64b49...5e3acc92

Changes: https://git.openjdk.org/jdk/pull/24746/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24746&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8354556
  Stats: 495 lines in 25 files changed: 469 ins; 6 del; 20 mod
  Patch: https://git.openjdk.org/jdk/pull/24746.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24746/head:pull/24746

PR: https://git.openjdk.org/jdk/pull/24746