[clang] ohos: fix ohos.c test case error with LLVM_ENABLE_PER_TARGET_RUNTIME_… (PR #121484)

[Carlo Cabrera via cfe-commits]

carlocab wrote:

> And one question: will llvm deprecate the old layout?

There was some desire to, but it seems to have fizzled out: https://discourse.llvm.org/t/rfc-time-to-drop-legacy-runtime-paths/64628

I imagine it'll happen eventually, but it will probably take a while.

> should we consider adding the old layout support for ohos?

I don't know enough about OHOS and its users to be able to say. If you're not sure: I suggest leaving out support for now, and someone who needs it can contribute support for it. But if we do leave support out: good error messages for users who happen to try to use/build it in the wrong configuration are probably essential.

https://github.com/llvm/llvm-project/pull/121484