RFR: 8312163: Crash in dominance check when compiling unnamed patterns

[Aggelos Biboudis]

The following fixes a crash in dominance checking involving unnamed patterns by teaching the method `patternDominated` how to handle `AnyPattern` nodes. The test file includes snippets with `_` that need to expose the same behavior as if `var _` was used in all nested positions in place of just `_`.

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Commit messages:
 - 8312163: Crash in dominance check when compiling unnamed patterns

Changes: https://git.openjdk.org/jdk/pull/14912/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=14912&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8312163
  Stats: 79 lines in 4 files changed: 76 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/14912.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14912/head:pull/14912

PR: https://git.openjdk.org/jdk/pull/14912