<AWT Dev> RFR: 8272481: [macos] javax/swing/JFrame/NSTexturedJFrame/NSTexturedJFrame.java fails

[Alexey Ushakov]

Update opacity only if the component is visible

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Commit messages:
 - 8272481: [macos] javax/swing/JFrame/NSTexturedJFrame/NSTexturedJFrame.java fails
 - 8272481: [macos] javax/swing/JFrame/NSTexturedJFrame/NSTexturedJFrame.java fails

Changes: https://git.openjdk.java.net/jdk/pull/5172/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=5172&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8272481
  Stats: 2 lines in 2 files changed: 0 ins; 1 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5172.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5172/head:pull/5172

PR: https://git.openjdk.java.net/jdk/pull/5172