test/javax/imageio/plugins/gif/TransparencyTest.java

rev 14031 : 8160974: [TESTBUG] Mark more headful tests with @key headful.

This is a backport of fe58d505fffd from jdk9. 228/596 hunks apply without
modifications. 16 hunks required manual rework. The remainder were for files
not present in jdk8u.

@@ -21,10 +21,11 @@
  * questions.
  */
 
 /*
  * @test
+ * @key headful
  * @bug 4339415
  * @summary Tests that GIF writer plugin is able to write images with BITMASK
  *          transparency
  */