RFR: 8250625: Compiler implementation of Pattern Matching for instanceof (Final) [v2]

[Jan Lahoda]

> This is the current proposed patch for the upcoming JEP 394, for pattern matching for instanceof.
> 
> A summary of changes:
> -making the feature permanent (non-preview)
> -making the binding variables non-final (as per current specification proposal)
> -producing a compile-time error for the case where the expression's type is a subtype of the type test pattern's type
>  (as per current specification proposal)
> -changing the AST structure so that the binding variable has a VariableTree in the AST. BindingPatternTree is preserved
>  and encloses the VariableTree. The reason is better consistency in the API, with nodes like CatchTree, EnhancedForLoop
>  Tree, etc.
> 
> This change will not be integrated until JEP 394 is targetted.

Jan Lahoda has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev
excludes the unrelated changes brought in by the merge/rebase. The pull request contains 15 additional commits since
the last revision:

 - Cleanup: using a null instead of List.of() as a parameter to JavaCompiler.getTask
 - Merge branch 'master' into patterns-instanceof3
 - Fixing more tests.
 - Correcting positions.
 - Improve the AST model.
 - Merge branch 'master' into patterns-instanceof3
 - Updating @since tags.
 - Merge branch 'master' into patterns-instanceof3
 - Cleaning up preview comments in javadoc.
 - Merge branch 'master' into patterns-instanceof3
 - ... and 5 more: https://git.openjdk.java.net/jdk/compare/737668da...5978bca0

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/559/files
  - new: https://git.openjdk.java.net/jdk/pull/559/files/69c7dce8..5978bca0

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=559&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=559&range=00-01

  Stats: 331339 lines in 1108 files changed: 314513 ins; 10715 del; 6111 mod
  Patch: https://git.openjdk.java.net/jdk/pull/559.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/559/head:pull/559

PR: https://git.openjdk.java.net/jdk/pull/559