RFR: 8315825: Open some swing tests [v2]

[Alisen Chung]

> Opening some swing tests:
> 1 javax/swing/LayoutComparator/4907772/bug4907772.java
> 2 javax/swing/LayoutComparator/4979794/bug4979794.java
> 3 javax/swing/LegacyGlueFocusTraversalPolicy/4765272/bug4765272.java
> 4 javax/swing/RootPaneChecking/RootPaneChecking.java

Alisen Chung has updated the pull request incrementally with one additional commit since the last revision:

  updated based on feedback

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/15830/files
  - new: https://git.openjdk.org/jdk/pull/15830/files/ec82c851..345185ba

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=15830&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=15830&range=00-01

  Stats: 14 lines in 4 files changed: 7 ins; 3 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/15830.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15830/head:pull/15830

PR: https://git.openjdk.org/jdk/pull/15830