RFR: 8315594: Open source few headless Swing misc tests [v2]

[Prasanta Sadhukhan]

> Few closed swing tests are open sourced

Prasanta Sadhukhan has updated the pull request incrementally with one additional commit since the last revision:

  Spacing issue

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Changes:
  - all: https://git.openjdk.org/jdk/pull/15577/files
  - new: https://git.openjdk.org/jdk/pull/15577/files/51e9731c..2a309750

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=15577&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=15577&range=00-01

  Stats: 5 lines in 1 file changed: 0 ins; 0 del; 5 mod
  Patch: https://git.openjdk.org/jdk/pull/15577.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15577/head:pull/15577

PR: https://git.openjdk.org/jdk/pull/15577