#133492 changed PathSet matching to also admit path prefixes, in addition to the previously-admitted suffixes. Unfortunately, this breaks how describe! handles some Steps. For the typical non-ShouldRun::suite_path Step, it will consume a path filter like "compiler" when eligible.

#133492 allowing prefix matching changed which Steps is permitted to "eat" the path filter first, which broke ./x test compiler --stage 0 and ./x build compiler --stage 0 due to the respective Step registration order and which Steps get to consume the path filter first:

• Running ./x test compiler only runs unit tests for rustc_codegen_cranelift #134916
• ./x build compiler --stage 0 reports success, but it shouldn't: deleting method used in another crate does not cause compilation to fail #134970

cc discussions at https://rust-lang.zulipchat.com/#narrow/channel/326414-t-infra.2Fbootstrap/topic/Mismatch.20between.20arg-filter.20vs.20.60--exclude.60.20filter.