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

8076468: Add @modules to tests in jdk_desktop test group
Reviewed-by: yan, alexsch

6817933: Setting the background of an HTML Widget changes the native Windows JFileChooser
Reviewed-by: alexsch