[mips] Remove tests which should have been deleted.

The two xfail tests for mis32r6 & mips64r6 were supposed
to be removed in r271301.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@271306 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed