Fixed unsafe code where a GC could occour after a Handle had been deferenced....

Fixed unsafe code where a GC could occour after a Handle had been deferenced.

  instances->set(i, *GetScriptWrapper(script));

GetScriptWrapper can call GC. The failure have only been seen on ARM, where
the g++ compiler pulls out the object from the instances handle to a register
before calling GetScriptWrapper causing set to be called on an object which
may have moved.

Marked a test on ARM as no longer flaky, whereas two other fails consistently
but that is no longer related to the problem fixed above.

BUG=1308895
Committed: http://code.google.com/p/v8/source/detail?r=444