ARM: add extra test for addrmode folding.

I was worried we might replace a mul with a mul+shift even if there were later
uses. Turns out to be unfounded but I'd just as well add an actual test for it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302051 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed