RFR: 8019816: [TEST_BUG][macosx] closed/java/awt/BasicStroke/DashZeroWidth.java not on EDT

[Roman Kennke]

This is a straightforward backport from the original jdk10 fix to jdk8u,
only adjusted new files locations.

Bug:
https://bugs.openjdk.java.net/browse/JDK-8019816
Original fix:
http://hg.openjdk.java.net/jdk/jdk/rev/080c3ab73c8d

JDK8u-backport:
http://cr.openjdk.java.net/~rkennke/backport-jdk8-JDK-8019816/webrev.00/

Good?

Thanks,
Roman