8170539: Test clashes with another test with a similar name

[Alan Bateman]

I need a reviewer to blow away a file in jdk9/dev/jdk:

hg rm 
test/java/awt/Focus/DisposedWindow/DisposeDialogNotActivateOwnerTest/DisposeDialogNotActivateOwnerTest.html

This is a dup of JDK-8169840 [1] but that change was pushed to 
jdk9/client rather than jdk9/dev, leaving jdk9/dev hosed. I can't hg 
import && hg import without causing problems for the next client -> dev 
integration so this is the reason for the next bug number and a new 
changeset.

-Alan

[1] http://hg.openjdk.java.net/jdk9/client/jdk/rev/983d90dfdadf