Ensure that JSGlobalContextRelease() performs garbage collection, even if there are other
        contexts in the current context's group.

        This is only really necessary when the last reference is released, but there is no way to
        determine that, and no harm in collecting slightly more often.

        * API/JSContextRef.cpp: (JSGlobalContextRelease): Explicitly collect the heap if it is not
        being destroyed.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@35917 268f45cc-cd09-0410-ab3c-d52691b4dbfc