Auto merge of #144064 - davidtwco:prefer-alias-over-env-for-sizedness, r=lcnr

prefer alias candidates for sizedness + auto trait goals

Fixes rust-lang/rust#143992

- abd07dec44437554520453f929c2b12d4eb8b11e: Reverts rust-lang/rust#144016 so that `MetaSized` bounds are checked properly, and updates all the tests accordingly, including making `tests/ui/sized-hierarchy/incomplete-inference-issue-143992.rs` fail when it shouldn't
- 90e61db9745f53d9aef21e3ebce0df19cc1389d7: Prefer alias candidates over parameter environment candidates for sizedness, auto and default traits. `tests/ui/sized-hierarchy/incomplete-inference-issue-143992.rs` passes again, but `tests/ui/generic-associated-types/issue-93262.rs` starts failing when it shouldn't
- e412062171925d0b40fdbeb5765c45087bdf0fe7: No longer require that predicates of aliases hold in well-formedness checking of the alias. `tests/ui/generic-associated-types/issue-93262.rs` passes again

Each commit updates all the tests to their new output so it should be easy enough to see what the impact of each change individually is. After all of the changes, tests that pass when they didn't before or vice versa:

- `tests/ui/extern/extern-types-size_of_val.rs`
    - Previously passing, but only because of rust-lang/rust#144016, now correctly errors
- `tests/ui/sized-hierarchy/incomplete-inference-issue-143992.rs`
    - Previously failing on next solver, only because rust-lang/rust#144016 only applied to the old solver, passing now with 90e61db9745f53d9aef21e3ebce0df19cc1389d7
- `tests/ui/sized-hierarchy/overflow.rs`
    - Previously passing, but only because of rust-lang/rust#144016, now correctly errors
- `tests/ui/generic-associated-types/issue-92096.rs`
    - Previously passing, due to e412062171925d0b40fdbeb5765c45087bdf0fe7
    - Fails to prove `C::Connecting<'placeholder>: Send` which is required when proving that the generator is `Send`. This is an instance of rust-lang/rust#110338.
- `tests/ui/higher-ranked/trait-bounds/normalize-under-binder/norm-before-method-resolution-opaque-type.rs`
    - Previously passing, now failing in the next solver, due to 03e0fdab6196e81b44356f42f03b6a0a224cf451
    - Expected that this test now fails as ambigious, see [Zulip](https://rust-lang.zulipchat.com/#narrow/channel/144729-t-types/topic/sizedness.20bounds.20in.20explicit_implied_predicates_of.20.28.23142712.29/near/526987384)

This had a crater run in rust-lang/rust#142712 (comment) alongside some other changes.

r? `@lcnr`
cc rust-lang/rust#142712 (this extracts part of that change)

Author: bors