8160974: [TESTBUG] Mark more headful tests with @key headful.
Reviewed-by: serb, simonis

8078855: [TEST_BUG] javax/swing/JComboBox/8032878/bug8032878.java fails in WindowsClassicLookAndFeel
Reviewed-by: alexsch, aivanov

8063107: Change open swing regression tests to avoid sun.awt.SunToolkit.realSync, part 2
8064573: [TEST_BUG] javax/swing/text/AbstractDocument/6968363/Test6968363.java is asocial pressing VK_LEFT and not releasing
8064575: [TEST_BUG] javax/swing/JEditorPane/6917744/bug6917744.java 100 times press keys and never releases
8064809: [TEST_BUG] javax/swing/JComboBox/4199622/bug4199622.java contains a lot of keyPress and not a single keyRelease
Reviewed-by: alexsch, pchelko

8032878: Editable combos in table do not behave as expected
Reviewed-by: alexp, alexsch
Contributed-by: alexey.ivanov@oracle.com