[mips] Simplify test for 5.0.1 (NFC)

Simplify testing that an emergency spill slot is used when MSA
is used so that it can be included in the 5.0.1 release.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@318172 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed