RFR: 8361298: SwingUtilities/bug4967768.java fails where character P is not underline [v2]

[Abhishek Kumar]

> For Windows and GTK L&F, mnemonic is visible when ALT key is pressed.
> Test instruction updated to reflect the desired behaviour .

Abhishek Kumar has updated the pull request incrementally with one additional commit since the last revision:

  minor text instruction update

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/26546/files
  - new: https://git.openjdk.org/jdk/pull/26546/files/f5248f70..ca742746

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=26546&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=26546&range=00-01

  Stats: 4 lines in 1 file changed: 0 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/26546.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26546/head:pull/26546

PR: https://git.openjdk.org/jdk/pull/26546