RFR: 8226933: [TEST_BUG]GTK L&F: There is no swatches or RGB tab in JColorChooser

[Abhishek Kumar]

There is no Swatches tab available for GTK Look and Feel due to the different ColorChooser UI design. Updated the test instructions.

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Commit messages:
 - Whitespace error fix
 - Test instructions change

Changes: https://git.openjdk.org/jdk/pull/20867/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=20867&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8226933
  Stats: 4 lines in 1 file changed: 2 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/20867.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20867/head:pull/20867

PR: https://git.openjdk.org/jdk/pull/20867