It's not ok for the unwinder to use a reference to elements
living in the m_faults array, since the unwinder can re-enter the VM
when calling destructors (or the FunctionExit hook). If one of those
re-entries does exception handling, it can modify m_faults.
Additionally, gets rid of VMPrepareThrow and instead just throw Object
and use the same case as we do when exceptions came from an extension.
I had to fix an assembler test catch handler to actually catch to keep
the assertion about m_faults on re-entry correct.
jdelong
bbdf9729fb