Create a wrapper pass for BranchProbabilityInfo.

Create a wrapper pass for BranchProbabilityInfo.

This new wrapper pass is useful when we want to do branch probability analysis conditionally (e.g. only in PGO mode) but don't want to add one more pass dependence.

http://reviews.llvm.org/D11241

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@242349 91177308-0d34-0410-b5e6-96231b3b80d8