Dist tools should receive some degree of smoke tests

[jieyouxu]

We should exercise the dist rustfmt, rust-analyzer, rustdoc, cargo etc. tools shipped as part of a dist toolchain in at least a basic manner. E.g.

• That the tools have reasonable version info.
• Links against the right libraries.
• Smoke test against a basic hello world input doesn't immediately explode.

[Mark-Simulacrum]

It might be worth putting this in promote-release as well (or only, to start) so that we test exactly what's about to ship, at least to Linux.

[jieyouxu]

I have some ideas for this, I'll write up some thoughts early next week on a proposal (I have some impl questions since I don't know the final bits of the dist/release workflows very well).