Fix PR3452 (an infinite loop bootstrapping) by disabling the recent

improvements to the EvaluateInDifferentType code.  This code works 
by just inserted a bunch of new code and then seeing if it is 
useful.  Instcombine is not allowed to do this: it can only insert
new code if it is useful, and only when it is converging to a more
canonical fixed point.  Now that we iterate when DCE makes progress,
this causes an infinite loop when the code ends up not being used.

llvm-svn: 63483