coreutils toolchain: Use statically linked linux amd64 variant

[malt3]

Uutils has a musl release artifact for linux amd64. In the future, it should probably also be possible to add a aarch64 musl toolchain. At the moment, this is not an upstream release artifact. I'm in the process of fixing this upstream.

Type of change

• Bug fix (fixes #701)

Test plan

• Covered by existing test cases

[mishazharov]

Oh no I accidentally duplicated this in https://github.com/aspect-build/bazel-lib/pull/720

I hope the maintainers take a look at one of these PRs

edit: I'll close my PR in favor of this one, because I think it's cleaner

[malt3]

@alexeagle @thesayyn gentle reminder. Could someone take a look at this?