Remove pointless assertion after r190376

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190565 91177308-0d34-0410-b5e6-96231b3b80d8
Fix comment to match what the assert actually enforces

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190566 91177308-0d34-0410-b5e6-96231b3b80d8
Move variable under condition where it is used

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190567 91177308-0d34-0410-b5e6-96231b3b80d8