Our private implementation of FailFast was likely introduced
when each individual application needed it's own code to
get Watson reports. The CLR takes care of this for us now,
so we don't need our implementation.
Our method CheckForSevereException was also introduced in
the early days of the CLR - the exceptions it was checking
for aren't actually raised the CLR anymore, they just FailFast.
I removed them as there is a tiny bit of overhead (in code size)
and also in the generated code, e.g. dynamic sites called the method.
Ilya