test/javax/swing/JFileChooser/6396844/TwentyThousandTest.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 6396844
  * @summary Tests memory leak for 20000 files
  * @author Sergey Malenkov
  * @library ../../regtesthelpers
  * @build Util