Removed trailing whitespace.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@180696 91177308-0d34-0410-b5e6-96231b3b80d8
Added statistics to count the number of retains/releases before/after optimization.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@180697 91177308-0d34-0410-b5e6-96231b3b80d8