[clang] [clang] Abort on unsupported uefi triples. (PR #124824)

[Paul Kirth via cfe-commits]

https://github.com/ilovepi commented:

This patch needs a test for the new driver logic. I'd also suggest adding some error handling in LLVM, so that it isn't possible to try an generate wrong code if this triple is supplied somewhere else (e.g. by another frontend or through opt).

https://github.com/llvm/llvm-project/pull/124824