Auto merge of #114414 - cjgillot:early-unnameable-test, r=petrochenkov

Make test harness lint about unnnameable tests.

Implementation of rust-lang/rust#113734 (comment)

About the options suggested in rust-lang/rust#36629 (comment): adding this case to unused_attribute was just more complicated. I'll try to understand a bit more what you had in mind in rust-lang/rfcs#2471 (comment)

This was just simpler to do in a standalone PR. I'll remove the corresponding changes from rust-lang/rust#113734 later.

r? `@petrochenkov`