[9] Review request for 8074921: OS X build broken by reference to XToolkit

[Alexander Zvegintsev]

Hello,

please review the fix
http://cr.openjdk.java.net/~azvegint/jdk/9/8074921/00/
for the issue
https://bugs.openjdk.java.net/browse/JDK-8074921
This fix removes reference to XToolkit from UNIXToolkit and moves 
awtLock to native.

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Thanks,

Alexander.