RFR: 8368219: Skip MenuDoubleShortcutTest on macOS & Linux

[Jayathirth D V]

MenuDoubleShortcutTest > nonMacMenuBarComesBeforeScene()/macSceneComesBeforeMenuBar() was failing intermittently and it was made more robust under [JDK-8364405](https://bugs.openjdk.org/browse/JDK-8364405) and it was verified with multiple runs and it was passing.

But looks like we still see this test failing in our CI. We need to skip this test and test fix will be worked upon under [JDK-8368074](https://bugs.openjdk.org/browse/JDK-8368074)

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Commit messages:
 - 8368219: Skip MenuDoubleShortcutTest on macOS & Linux

Changes: https://git.openjdk.org/jfx/pull/1916/files
  Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=1916&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8368219
  Stats: 2 lines in 1 file changed: 2 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jfx/pull/1916.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1916/head:pull/1916

PR: https://git.openjdk.org/jfx/pull/1916