RFR: 8075916: The regression-swing case failed as colored text is not shown on disabled checkbox and radio button with Nimbus LAF

[Prasanta Sadhukhan]

CheckBox.disabledText and RadioButton.disabledText color UIProperty is not honoured by Nimbus L&F when disabled text is drawn for JCheckBox and JRadioButton, so disabled text color was rendered incorrectly.
Fix is to honour these UIProperty color if they are set by user, else use the color from the component or via getColorForState().

Closed test as mentioned in JBS is used to check the fix.

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Commit messages:
 - 8075916: The regression-swing case failed as colored text is not shown on disabled checkbox and radio button with Nimbus LAF

Changes: https://git.openjdk.org/jdk/pull/10177/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10177&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8075916
  Stats: 8 lines in 1 file changed: 8 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/10177.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10177/head:pull/10177

PR: https://git.openjdk.org/jdk/pull/10177