[patch] Start fixing pr24429

[Rafael Espíndola via llvm-commits]

> It does remove information from MCObjectFileInfo though. Is it really
> desirable to pick the Triple to be the one that gets to keep this
> information, rather than the other way around? I don't have a clear
> view of where this is headed.

Even if we move it out of the triple, IMHO it is a good step to first
have a single location.

And given that we support things like x86_64-pc-windows-elf in the
command line, having this information on the Triple c++ object also
seems reasonable to me. If we remove it from one place we should also
remove it from the other.

Cheers,
Rafael