RFR: 8265439: [TestBug] Enable and fix ignored unit tests in MenuItemTest [v2]

[Ajit Ghaisas]

> This PR enables ignored unit tests from MenuItemTest and fixes them.
> 2 ignored tests are fixed. 
> 4 ignored tests are removed.
> 2 new tests are added.
> 
> **Before fix :**
> total tests = 89
> failures = 0
> ignored tests =  6
> 
> **After fix :**
> total tests = 89
> failures = 0
> ignored tests =  0

Ajit Ghaisas has updated the pull request incrementally with one additional commit since the last revision:

  remove incorrect tests

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

Changes:
  - all: https://git.openjdk.java.net/jfx/pull/466/files
  - new: https://git.openjdk.java.net/jfx/pull/466/files/25516821..49293826

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jfx&pr=466&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jfx&pr=466&range=00-01

  Stats: 16 lines in 1 file changed: 0 ins; 16 del; 0 mod
  Patch: https://git.openjdk.java.net/jfx/pull/466.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/466/head:pull/466

PR: https://git.openjdk.java.net/jfx/pull/466