[LSR] Add llc testcase for r207271/r207569.

See PR19608 for the details but to summarize it was easy to modify the .ll
file to get the desired def-use ordering.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207887 91177308-0d34-0410-b5e6-96231b3b80d8