RFR: 8376423: Test javax/swing/plaf/metal/MetalUtils/bug6190373.java failed: ClassCastException: class java.lang.Character cannot be cast to class javax.swing.Painter

[Phil Race]

AppContext is removed from Swing LAF state. Tests which require it are deleted.

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

Commit messages:
 - v
 - 8376423
 - 8376423

Changes: https://git.openjdk.org/jdk/pull/29437/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=29437&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8376423
  Stats: 236 lines in 6 files changed: 36 ins; 192 del; 8 mod
  Patch: https://git.openjdk.org/jdk/pull/29437.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29437/head:pull/29437

PR: https://git.openjdk.org/jdk/pull/29437