Rollup merge of #148771 - fmease:iat-reinstate-early-elim, r=BoxyUwU

IAT: Reinstate early bailout

Apparently, some people are already using IATs in their projects and get blocked by rust-lang/rust#142006 (comment) (cc dupes rust-lang/rust#143952 & rust-lang/rust#148535). Since the (temporary) fix is so trivial, let's just do it.

Addresses rust-lang/rust#142006 (comment).

cc ```@luissantosHCIT``` (rust-lang/rust#148535).

r? ```@BoxyUwU```

Author: Zalathar