RFR: 8309935: Mac - SystemMenuBar, IndexOutOfBoundsException on change [v2]

[Florian Kirmaier]

> Fixing JDK-8309935 and providing a test for it.

Florian Kirmaier has updated the pull request incrementally with one additional commit since the last revision:

  small changes based on code review

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

Changes:
  - all: https://git.openjdk.org/jfx/pull/1152/files
  - new: https://git.openjdk.org/jfx/pull/1152/files/8d9460e7..5ef8357a

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=1152&range=01
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=1152&range=00-01

  Stats: 27 lines in 1 file changed: 25 ins; 2 del; 0 mod
  Patch: https://git.openjdk.org/jfx/pull/1152.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1152/head:pull/1152

PR: https://git.openjdk.org/jfx/pull/1152