[8u40] Request for approval: 8047288. Endless loop in EDT on Mac

[artem malinko]

Hello!

This is a request to backport a jdk9 fix into jdk8u-dev.

Description:
Window.isFocusableWindow() could lead to deadlock if it is invoked on 
AppKit thread. Fix caches result of Window.isFocusableWindow() on a peer 
level and method is not invoked on AppkitThread.
https://bugs.openjdk.java.net/browse/JDK-8047288

Fix included in jdk9:
http://hg.openjdk.java.net/jdk9/client/jdk/rev/cffba41b6194

Review thread:
http://mail.openjdk.java.net/pipermail/awt-dev/2014-July/008281.html

The patch for jdk8 is identical to one in jdk9.