[block-freq] Add the APInt method extractBit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@197271 91177308-0d34-0410-b5e6-96231b3b80d8
[block-freq] Add the method APInt::nearestLogBase2().

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@197272 91177308-0d34-0410-b5e6-96231b3b80d8