Auto merge of #44679 - oli-obk:clippy_ci, r=alexcrichton

Add clippy to `toolstate.toml`

r? @alexcrichton

cc @Manishearth

I have no idea how to get clippy working... it needs proc macros, and I think I did everything right (I just did what the cargo step is doing), but it's not working:

```
error: libproc_macro-6210e4b46662ec28.so: cannot open shared object file: No such file or directory
  --> src/tools/clippy/clippy_lints/src/lib.rs:47:1
   |
47 | extern crate serde_derive;
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^

error: libproc_macro-6210e4b46662ec28.so: cannot open shared object file: No such file or directory
  --> src/tools/clippy/clippy_lints/src/lib.rs:47:1
   |
47 | extern crate serde_derive;
   | ^
```

It's especially weird since it used to work

Anyway. Fixing it can be left for a future PR, this one adds it to CI, but marks it as "broken"