Moving Cost Tables up to share with other targets

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173382 91177308-0d34-0410-b5e6-96231b3b80d8
Avoid creating duplicate CFG edges in the IfConversion pass.

Patch by Stefan Hepp.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173395 91177308-0d34-0410-b5e6-96231b3b80d8