8185500: [TESTBUG] Add keywords headful/printer in java/awt and javax tests.
Summary: Add new keyword 'printer'. Some minor test fixes to show headless exception. Add some @requires windows.
Reviewed-by: serb, mbaesken

8161902: [PIT][TEST_BUG]sun/awt/image/OffScreenImageSource/ImageConsumerUnregisterTest.java compilation fails
Reviewed-by: prr
Contributed-by: jayathirth.d.v@oracle.com

8160421: Regression: JDK-8139192 causes NPE in java.awt.Toolkit.createCustomCursor()
Reviewed-by: flar, prr