Auto merge of #33625 - alexcrichton:rustbuild-moar-tests, r=aturon

rustbuild: Touch up some test suites

This adds in some missing test suites, primarily a few pretty suites. It also starts optimizing tests by default as the current test suite does, but also recognizes `--disable-optimize-tests`.

Currently the optimization of tests isn't recognized by crate tests because Cargo doesn't support the ability to compile an unoptimized test suite against an optimized library. Perhaps a feature to add, though!

diff --cc src/librustc_metadata/creader.rs
Simple merge