[clang] Enable aarch64-amazon-linux triple (PR #82232)

[Byoungchan Lee via cfe-commits]

bc-lee wrote:

I'm not the owner of this code, but I just dropped by to say that
I don't think this patch will be accepted. A few lines above your changes,
there is a comment that says, "Please don't add more elements to *Triples.".

@MaskRay is working to reduce the number of target triples like 20d497c26fc95c80a1bacb38820d92e5f52bec58
and I think this patch goes against his goals.

https://github.com/llvm/llvm-project/pull/82232