Rollup merge of #82802 - jyn514:build-rustdoc-fullmake, r=Mark-Simulacrum
Rollup merge of #82802 - jyn514:build-rustdoc-fullmake, r=Mark-Simulacrum

Build rustdoc for run-make tests, not just run-make-fulldeps

Rustdoc almost never needs a full stage 2 compiler, and requiring
rustdoc tests to be in run-make-fulldeps adds a lot of compile time for
no reason.

This is the same change from https://github.com/rust-lang/rust/pull/81197, but separated into its own PR. I ran into this again today while working on https://github.com/rust-lang/docs.rs/issues/1302.
r? ```@Mark-Simulacrum```

aidancully/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust,graydon/rust