[7u6] Request for approval for CR 7124326: [macosx] An issue similar to autoshutdown one in two AppContexts situation.

[Anthony Petrov]

Bug: http://bugs.sun.com/view_bug.do?bug_id=7124326
Webrev: 
http://cr.openjdk.java.net/~anthony/7u6-15-AppContextAutoshutdown-7124326.0/
Review thread: 
http://mail.openjdk.java.net/pipermail/macosx-port-dev/2012-June/004529.html
Reviewers: Artem Ananiev, Leonid Romanov

Note: this is a 100% direct back-port of the same fix from JDK 8.

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best regards,
Anthony