Revert "Populate effective visibilities in `rustc_privacy`"
This reverts commit cff85f22f5, cc #110907. It needs to be fixed, but there are too many issues being reported that I wanted to put up a revert until a proper fix can be committed.
Fixes a ton of issues where private but still reachable impls were missing during codegen:
Fixes#111320Fixes#111321Fixes#111334Fixes#111357Fixes#111368Fixes#111373Fixes#111377Fixes#111386Fixes#111387
`@bors` p=1
r? `@petrochenkov`