RFR: JDK-8282046: Create a regression test for CCC8000326 [v2]

[Srinivas Mandalika]

> Create a regression test for CCC8000326
> 
> Issue is identified by [JDK-8000326](https://bugs.openjdk.java.net/browse/JDK-8000326), which identifies that after focus moves into JMenuBar, whose focus traversal key is disabled by default, it never moves to other focusable component.
>  
> By default, pressing the Tab key does not transfer focus from a JMenuBar which is added to a container together with other Swing components, because the focusTraversalKeysEnabled property of JMenuBar is set to false. To resolve this, you should call the JMenuBar.setFocusTraversalKeysEnabled(true) method.
>  
> The test verifies focus traversal for the above described scenario.

Srinivas Mandalika has updated the pull request incrementally with one additional commit since the last revision:

  Review comments fixed: file name changed, volatile dimension, static call to doTest

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/7512/files
  - new: https://git.openjdk.java.net/jdk/pull/7512/files/1214de24..c0fcaf89

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=7512&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=7512&range=00-01

  Stats: 14 lines in 1 file changed: 4 ins; 4 del; 6 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7512.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7512/head:pull/7512

PR: https://git.openjdk.java.net/jdk/pull/7512