[ARM] Make testcase more explicit. NFC.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223841 91177308-0d34-0410-b5e6-96231b3b80d8
[Hexagon] [NFC] Cleaning up unused classes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223845 91177308-0d34-0410-b5e6-96231b3b80d8
Remove redundant variable.

Tested by adding assert(LoopVectorPreHeader == VecPreheader) on LLVM
test suite and SPECs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223847 91177308-0d34-0410-b5e6-96231b3b80d8