[Rev 01] RFR: 8244195: [TEST_BUG] Convert the system tests TabPanePermuteGetTabsTest to unit test

[Ambarish Rapte]

> As discussed [here](https://github.com/openjdk/jfx/pull/201#issuecomment-621772586) during #201 , This PR converts the
> system tests in TabPanePermuteGetTabsTest.java to unit test.
> Thanks @kleopatra , for providing the test. I have added few more tests and found few failures.
> [JDK-8245528](https://bugs.openjdk.java.net/browse/JDK-8245528) is created to fix these failures, the failing tests are
> currently ignored using this bug.
> Please take a look.

Ambarish Rapte has updated the pull request incrementally with one additional commit since the last revision:

  fix review comments

-------------

Changes:
  - all: https://git.openjdk.java.net/jfx/pull/230/files
  - new: https://git.openjdk.java.net/jfx/pull/230/files/9e12c606..687083b7

Webrevs:
 - full: https://webrevs.openjdk.java.net/jfx/230/webrev.01
 - incr: https://webrevs.openjdk.java.net/jfx/230/webrev.00-01

  Stats: 2 lines in 1 file changed: 1 ins; 1 del; 0 mod
  Patch: https://git.openjdk.java.net/jfx/pull/230.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/230/head:pull/230

PR: https://git.openjdk.java.net/jfx/pull/230