Specify a target cpu in test case

Hopefully, this makes the bots happy

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@284048 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit 87e888e3b555baed76bb4ffe825f442b590af57e)
1 file changed