Headful clients failing with --illegal-access=deny

The following headful tests are currently failing with --illegal-access=deny as they do deep reflection on private members of classes in exported packages or members of classes in non-exported packages. The @modules tags on these tests need to be updated in advance of changing the default to deny illegal access.

java/awt/Toolkit/DisplayChangesException/DisplayChangesException.java
java/awt/event/SequencedEvent/MultipleContextsUnitTest.java
javax/accessibility/6714324/TabbedPaneMemLeak.java
com/sun/java/swing/plaf/windows/RevalidateOnPropertyChange.java

I've attached a patch to his bug with the updates the @modules needed to fix these issues.