[jdk17] RFR: 8268859: jshell throws exception while parsing illegal "case true"

[Jan Lahoda]

Currently, broken case labels like `case true t` parse as patterns, whose type is `true`, which then fails later during annotation handling. This patch is trying to improve (and fix) the pattern/expression disambiguation again, making it more explicit than before. With this patch, only labels that begin with `<type> <name>` should be considered patterns.

The recently added no-preview part of `SwitchErrors` is moved to `PatternErrorRecovery.java`, because that indeed turned out to be difficult to maintain.

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

Commit messages:
 - Formatting, cleanup.
 - Adding missing files.
 - Readding SuppressWarnings.
 - Merge branch 'master' into JDK-8268859
 - Improving disambiguation of expressions and patterns.
 - Merge branch 'master' into JDK-8268859
 - 8268859: jshell throws exception while parsing illegal "case true"

Changes: https://git.openjdk.java.net/jdk17/pull/202/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk17&pr=202&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8268859
  Stats: 548 lines in 12 files changed: 279 ins; 206 del; 63 mod
  Patch: https://git.openjdk.java.net/jdk17/pull/202.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk17 pull/202/head:pull/202

PR: https://git.openjdk.java.net/jdk17/pull/202