RFR: 8346260: Test "javax/swing/JOptionPane/bug4174551.java" failed because the font size of message "Hi 24" is not set to 24 in Nimbus LookAndFeel

[Prasanta Sadhukhan]

"OptionPane.buttonFont" and "OptionPane.messageFont" property are ignored for Nimbus L&F as for Nimbus, lookup calls initiated by BasicOptionPaneUI#configureButton and BasicOptionPaneUI#configureMessageLabel, were redirected via SynthContext so UIManager.getDefaults L&F properties were ignored..
Added way to honor this properties for SynthOptionPaneUI..It could be later extended for other UI properties for other widgets which may need UIManager lookup..

-------------

Commit messages:
 - dummy commit
 - 8346260: Test javax/swing/JOptionPane/bug4174551.java failed because the font size of message Hi 24 is not set to 24 in Nimbus LookAndFeel

Changes: https://git.openjdk.org/jdk/pull/22908/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22908&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8346260
  Stats: 9 lines in 2 files changed: 8 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/22908.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22908/head:pull/22908

PR: https://git.openjdk.org/jdk/pull/22908