RFR: 8316061: Open source several Swing RootPane and Slider related tests

[Tejesh R]

Open sourcing these Swing RootPane and Slider related tests:

javax/swing/JRootPane/4207333/bug4207333.java
javax/swing/JRootPane/4224113/bug4224113.java
javax/swing/JRootPane/4627806/bug4627806.java
javax/swing/JSlider/4200901/bug4200901.java
javax/swing/JSlider/4203754/bug4203754.java

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Commit messages:
 - Open sourcing few RootPane and Slider test

Changes: https://git.openjdk.org/jdk/pull/15734/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15734&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8316061
  Stats: 302 lines in 5 files changed: 302 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/15734.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15734/head:pull/15734

PR: https://git.openjdk.org/jdk/pull/15734