RFR: 8338000: Remove GlassFullscreenWindow

[Martin Fox]

The GlassFullscreenWindow class hasn't been instantiated since applet support was removed (JDK-8201538). This PR removes the class and the one (unused) member variable of that type.

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Commit messages:
 - Merge remote-tracking branch 'upstream/master' into macfscleanup
 - Removed old fullscreen handling cruft.

Changes: https://git.openjdk.org/jfx/pull/1641/files
  Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=1641&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8338000
  Stats: 223 lines in 11 files changed: 0 ins; 221 del; 2 mod
  Patch: https://git.openjdk.org/jfx/pull/1641.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1641/head:pull/1641

PR: https://git.openjdk.org/jfx/pull/1641