Auto merge of #7045 - Eh2406:resolver-test/debug-cleanup, r=alexcrichton

Resolver test/debug cleanup

This is several small things salvaged from abandoned PRs and implemented on top of #7011

In working on this I noted that the prop tests are very sensitive to whether backtrace are turned on. Maybe we should set that env to 0 for that builder?

diff --cc crates/resolver-tests/src/lib.rs
Simple merge