Auto merge of #147299 - compiler-errors:hr-norm, r=jackh726

Don't normalize higher-ranked assumptions if they're not used

See the comment in the code.

Normalizing these assumptions may cause us to register things like new placeholder outlives obligations that cause higher-ranked lifetime errors, and this is problematic if we're not even using these assumptions in borrowck.

Fixes rust-lang/rust#147244
Fixes rust-lang/rust#147285

Author: bors