RFR: 8359759: Remove the FXPermission class

[Lukasz Kostyra]

As PR title says, this change removes the FXPermission class.

The class was not used in any place in JavaFX. It was marked deprecated in JFX24 and also marked for-removal, with plans to remove it in 26.

I ran both local Windows tests and CI tests with this change and, as expected, there was no difference in test results (all passed).

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Commit messages:
 - Remove FXPermission

Changes: https://git.openjdk.org/jfx/pull/2002/files
  Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=2002&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8359759
  Stats: 71 lines in 1 file changed: 0 ins; 71 del; 0 mod
  Patch: https://git.openjdk.org/jfx/pull/2002.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/2002/head:pull/2002

PR: https://git.openjdk.org/jfx/pull/2002