<Swing Dev> RFR: 8271923: [macos] the text color on the selected disabled tabbed pane button remains white making text unreadable

[Prasanta Sadhukhan]

It is seen that  if a JTabbedPane is unfocused, it's title is painted with **white** text on grey background 
as opposed to **black** text on grey background in unfoucsed native app on macOSX Catalina
and is somewhat not legible. 
This can be seen with SwingSet2 demo with InternalFrame or JTabbedPane demo and any native app, making focus toggle between the two.

Issue was TabbedPane always draw with "selectedTabTitleNormalColor" which is white. Although Aqua L&F defined selectedTabTitleDisabledColor but it is not used as TabbedPane does not check if focus is there in current frame and draw accordingly, which native app does.

Proposed fix is to check for frame is active or not and draw text color accordingly. 
Since it is not affecting BigSur (where even if native app active or not text is always drawn in same color), it is only restricted to Catalina and lower.

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Commit messages:
 - Fix
 - Fix

Changes: https://git.openjdk.java.net/jdk/pull/5217/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=5217&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8271923
  Stats: 7 lines in 2 files changed: 4 ins; 0 del; 3 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5217.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5217/head:pull/5217

PR: https://git.openjdk.java.net/jdk/pull/5217