RFR: 8300543 Compiler Implementation for Pattern Matching for switch

[Jan Lahoda]

This is the first draft of a patch for JEP 440 and JEP 441. Changes included:

 - the pattern matching for switch and record patterns features are made final, together with updates to tests.
 - parenthesized patterns are removed.
 - qualified enum constants are supported for case labels.

This change herein also includes removal record patterns in for each loop, which may be split into a separate PR in the future.

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

Commit messages:
 - Fixing test.
 - Assignment to variables declared outside of guard not allowed.
 - Adding test for incorrectly used guards.
 - Merge branch 'master' into JDK-8300543
 - Merge branch 'master' into JDK-8300543
 - Removing trailing whitespace
 - Fixing tests.
 - Post-merge fix.
 - Merge remote-tracking branch 'jdk/reduce-exhaustiveness' into JDK-8300543
 - Support for 'overfitting' patterns.
 - ... and 15 more: https://git.openjdk.org/jdk/compare/cd7d53c8...57445212

Changes: https://git.openjdk.org/jdk/pull/13074/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13074&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8300543
  Stats: 3662 lines in 157 files changed: 1552 ins; 1682 del; 428 mod
  Patch: https://git.openjdk.org/jdk/pull/13074.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13074/head:pull/13074

PR: https://git.openjdk.org/jdk/pull/13074