Write a regression test for JDK-4164779 : JSplitPane keyboard navigation does not support F6 and Ctrl+Tab

Issue:
The specified keyboard support for JSplitPane also requires F6 and Ctrl+Tab (navigate out) for the JSplitPane. Those are currently not implemented.

F6 is supposed to move the focus from the current focused component on one side of the JSplitPane to the other side of the JSplitPane without having to tab through to that.

Ctrl+Tab is supposed to move the input focus from whatever component inside the JSplitPane that has the focus to the next component outside the JSplitPane.

Testing:
Java 1.4.0 -> Test Failed.
$ ./j2sdk1.4.0/bin/java JSplitPaneTest
Verifier 1 failed
Verifier 2 failed
Verifier 3 failed
Verifier 4 failed
Test Failed.

Java 1.4.1 -> Test Passed.
$ ./j2sdk1.4.1/bin/java JSplitPaneTest
Verifier 1 passed
Verifier 2 passed
Verifier 3 passed
Verifier 4 passed
Test Passed.