Add code to resize the CSEMap hash table. This doesn't speedup codegen of

Add code to resize the CSEMap hash table.  This doesn't speedup codegen of
kimwitu, but seems like a good idea from a "avoid performance cliffs" standpoint :)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@29675 91177308-0d34-0410-b5e6-96231b3b80d8