RFR: 8303374: Implement JEP 455: Primitive Types in Patterns, instanceof, and switch (Preview) [v57]

[Aggelos Biboudis]

> This is the proposed patch for Primitive types in patterns, instanceof, and switch (Preview).
> 
> Draft spec here: https://cr.openjdk.org/~abimpoudis/instanceof/latest/

Aggelos Biboudis has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 78 commits:

 - Merge branch 'master' into primitive-patterns
 - Update summary in ExactnessConversionsSupportTest
 - Address review by Jan
 - Remove redundant null check  and introduce a const boolean for unconditionally exact pairs
 - Small fix in Javadoc
 - Tidy up Javadoc of Lower.visitTypeTest
 - Tidy up Javadoc of IllegalArgumentException in typeSwitch
 - Improve readability in SwitchBootstraps
 - Update year
 - Cleanup redundant clone
 - ... and 68 more: https://git.openjdk.org/jdk/compare/ec56c72b...f68748b1

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Changes: https://git.openjdk.org/jdk/pull/15638/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15638&range=56
  Stats: 3818 lines in 45 files changed: 3385 ins; 212 del; 221 mod
  Patch: https://git.openjdk.org/jdk/pull/15638.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15638/head:pull/15638

PR: https://git.openjdk.org/jdk/pull/15638