[llvm] [clang] Reapply #2 [clang-repl] [test] Make an XFAIL more precise (#70991) (PR #71168)

[Martin Storsjö via cfe-commits]

mstorsjo wrote:

Posting for a second review instead of just relanding the patch as is; in order to check the host triple, I had to add the `host=triple` string; it was previously only available for tests under `llvm/test`, but let's move it to the common llvm test configuration just like the `target=triple` strings, so that it is available for tests under clang as well.

https://github.com/llvm/llvm-project/pull/71168