RFR: 8316388: Opensource five Swing component related regression tests

[Alexander Zuev]

Clean up five more tests.

test/jdk/javax/swing/JDesktopPane/4132993/bug4132993.java
test/jdk/javax/swing/JDesktopPane/4773378/bug4773378.java
test/jdk/javax/swing/JEditorPane/4325606/bug4325606.java
test/jdk/javax/swing/JEditorPane/4330998/bug4330998.java
test/jdk/javax/swing/JEditorPane/4694598/FrameContent.html
test/jdk/javax/swing/JEditorPane/4694598/bug4694598.java

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Commit messages:
 - 8316388: Opensource five Swing component related regression tests

Changes: https://git.openjdk.org/jdk/pull/18184/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=18184&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8316388
  Stats: 454 lines in 6 files changed: 454 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/18184.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18184/head:pull/18184

PR: https://git.openjdk.org/jdk/pull/18184