RFR: 8332222: Linux Debian: Maximized stage shrinks when opening another stage

[Thiago Milczarek Sayao]

This fixes two bugs appointed on the JBS issue:

1) Sometimes window was moving to the top left corner - seems to be a bug somewhere in `gdk_window_get_origin` when used before map (a X concept when the window appears). The change is to ignore the configure events (happens when location or size changes) until window is mapped. Before map java is notified in the `set_bounds` function.

This seems to happen on newer versions of linux distros.

2) Specific to KDE, in the case of the example provided, when an MODAL window pops, it calls `set_enabled` `false` on the child (or all other windows if APPLICATION_MODAL) which causes it to update the window constraints. When maximized, the constraints where applied anyways, causing the window to still be maximized but not show as maximized. The change is to not apply constraints when not floating (meaning floating on the screen - not maximized, fullscreen or iconified).

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Commit messages:
 - Fix
 - Teste
 - Teste
 - Teste
 - Fix 8332222

Changes: https://git.openjdk.org/jfx/pull/1460/files
  Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=1460&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8332222
  Stats: 45 lines in 3 files changed: 28 ins; 6 del; 11 mod
  Patch: https://git.openjdk.org/jfx/pull/1460.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1460/head:pull/1460

PR: https://git.openjdk.org/jfx/pull/1460