RFR: 8319147: Add regression test for JDK-8317836

[Prasanta Sadhukhan]

A manual regression test for JFXPanel orientation fix in [JDK-8317836](https://bugs.openjdk.org/browse/JDK-8317836) is added

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Commit messages:
 - Test fix
 - Test fix

Changes: https://git.openjdk.org/jfx/pull/1276/files
 Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=1276&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8319147
  Stats: 120 lines in 1 file changed: 120 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jfx/pull/1276.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1276/head:pull/1276

PR: https://git.openjdk.org/jfx/pull/1276