[8u] RFR: 8159690: [TESTBUG] Mark headful tests with @key headful.

[Jonathan Dowland]

Hello,

Please review this backport of JDK-8159690 to 8u, for parity with
Oracle 8u271.

Bug: https://bugs.openjdk.java.net/browse/JDK-8159690
jdk9 patch: http://hg.openjdk.java.net/jdk9/jdk9/jdk/rev/980da45565c8

webrev:
    https://jmtd.net/tmp/JDK-8159690/

542/842 hunks applied directly from the original patch. 44 I resolved
manually.  The remaining hunks are for filenames that do not exist in
jdk8u. Those basenames are listed here:
    https://jmtd.net/tmp/JDK-8159690/basenames_not_in_tree.txt

Note that there are two different tests with the basename
"ImageTransferTest.java", only one of which is in jdk8u.


Thank you,

-- 
���� Jonathan Dowland <jdowland at redhat.com>
Senior Software Engineer, OpenJDK, Red Hat