Auto merge of #81746 - bjorn3:cg_clif_rustup_component, r=Mark-Simulacrum

Distribute cg_clif as rustup component on the nightly channel

This makes it possible to use cg_clif using:

```bash
$ rustup component add rustc-codegen-cranelift-preview --toolchain nightly
$ RUSTFLAGS="-Zcodegen-backend=cranelift" cargo +nightly build
```

cc rust-lang/compiler-team#405.
r? `@Mark-Simulacrum`

Author: bors