RFR: 8302344: Compiler Implementation for Unnamed patterns and variables (Preview) [v26]

[Aggelos Biboudis]

> This PR implements [JEP 443](https://openjdk.org/jeps/443), the preview feature for Unnamed Patterns and Variables in Java.
> 
> Draft Spec: https://cr.openjdk.org/~abimpoudis/unnamed/latest/

Aggelos Biboudis has updated the pull request incrementally with one additional commit since the last revision:

  Simplify `LambdaClassifier`
  
  Co-authored-by: Maurizio Cimadamore <maurizio.cimadamore at oracle.com>

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/13528/files
  - new: https://git.openjdk.org/jdk/pull/13528/files/175d6459..804d41af

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=13528&range=25
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13528&range=24-25

  Stats: 27 lines in 1 file changed: 16 ins; 8 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/13528.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13528/head:pull/13528

PR: https://git.openjdk.org/jdk/pull/13528