Auto merge of rust-lang#113450 - Nilstrieb:src/bootstrap/test.rs, r=flip1995

Fail the build if clippy tests don't pass

This was removed in
rust-lang@de69d55#diff-8479eab02701e686aedb15b567dc8fc31220c6e4efb9565ccc9d662b7fee2214 which caused CI to ignore clippy failures. This adds back the exit, which should cause CI to fail again if a test is broken (like right now, as clippy tests are broken on master).

Also see https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/CI.20doesn't.20care.20about.20clippy.20test.20failures.20but.20only.20sometime

r? flip1995

Author: bors