Writing a regression test for JDK9, we should have in mind that this release will be modularized, and most of the deprecated and non-public classes and methods will be not available to a user program.
A test is not exactly a user program but to grant it access to (for instance) sun.awt.* classes, we will have to give it some special treatment, pass additional XX flags etc. Let's try to avoid that without real necessity such as testing internal API.

Using sun.awt.OSInfo (should use jdk/testlibrary/OSInfo instead) :
java/awt/Desktop/8064934/bug8064934.java
javax/swing/JFileChooser/8062561/bug8062561.java
java/awt/SplashScreen/FullscreenAfterSplash/FullScreenAfterSplash.java

Using sun.awt.OSInfo and SunToolkit.realSync():
javax/swing/JButton/4796987/bug4796987.java (and realSync)

sun.awt.OSInfo left there by mistake in my previous fix:
javax/swing/JPopupMenu/6827786/bug6827786.java