Rollup merge of rust-lang#84484 - jyn514:check-tools, r=Mark-Simulacrum

Don't rebuild rustdoc and clippy after checking bootstrap

This works by unconditionally passing -Z unstable-options to the
compiler. This has no affect in practice since bootstrap doesn't use
`deny(rustc::internal)`.

Fixes rust-lang#82461.

r? ```@Mark-Simulacrum```

Author: jackh726

clippy_lints/src/lib.rs

@@ -17,7 +17,7 @@
 // warn on lints, that are included in `rust-lang/rust`s bootstrap
 #![warn(rust_2018_idioms, unused_lifetimes)]
 // warn on rustc internal lints
-#![deny(rustc::internal)]
+#![warn(rustc::internal)]
 
 // FIXME: switch to something more ergonomic here, once available.
 // (Currently there is no way to opt into sysroot crates without `extern crate`.)

src/driver.rs

@@ -4,7 +4,7 @@
 // warn on lints, that are included in `rust-lang/rust`s bootstrap
 #![warn(rust_2018_idioms, unused_lifetimes)]
 // warn on rustc internal lints
-#![deny(rustc::internal)]
+#![warn(rustc::internal)]
 
 // FIXME: switch to something more ergonomic here, once available.
 // (Currently there is no way to opt into sysroot crates without `extern crate`.)