Change this to an IR test instead of an assembly test (as per comment in r171134).
Change this to an IR test instead of an assembly test (as per comment in r171134).

This makes the test not dependent on LLVM & won't vary/break based on LLVM
codegen related changes. Appropriately testing at the Clang level what was
fixed at the Clang level originally (in r124210).

git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@171175 91177308-0d34-0410-b5e6-96231b3b80d8

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