[clang] [llvm] Remove support for 3DNow!, both intrinsics and builtins. (PR #96246)

[James Y Knight via cfe-commits]

jyknight wrote:

Thanks for the report! Looks like I missed some 3dnow mentions in llvm/lib/TargetParser/X86TargetParser.cpp, so `-mno-mmx` is still emitting this feature.

I don't believe it should have any impact other than the warning spam, but I will fix it.

https://github.com/llvm/llvm-project/pull/96246