[macosx] Action registered for keyboard shortcut is called twice

[Mitsuhiro Yamamoto]

Hi there,

The fix for the bug shown below has been applied since Java 9, but it
doesn't seem to be applied to Java 8.
So could you backport this fix to Java 8?
https://bugs.openjdk.java.net/browse/JDK-8139169

For reference, this is the fix commit for it in openjdk/jdk.
https://github.com/openjdk/jdk/commit/7d9d3a469949a3874f35ebacb140e0aaf49c12f0

Best Regards
Mit