RFR: 8303374: Implement JEP 455: Primitive Types in Patterns, instanceof, and switch (Preview) [v53]

[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 incrementally with one additional commit since the last revision:

  Tidy up Javadoc of Lower.visitTypeTest

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Changes:
  - all: https://git.openjdk.org/jdk/pull/15638/files
  - new: https://git.openjdk.org/jdk/pull/15638/files/b77d2316..44634684

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=15638&range=52
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=15638&range=51-52

  Stats: 28 lines in 1 file changed: 9 ins; 5 del; 14 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