CodeGen: BlockPlacement: Minor probability changes.

Qin may be large, and Succ may be more frequent than BB. Take these both into
account when deciding if tail-duplication is profitable.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@299891 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed