Rollup merge of #120899 - compiler-errors:non-wf-alias, r=lcnr

Gracefully handle non-WF alias in `assemble_alias_bound_candidates_recur`

See explanation in test. I think it's fine to delay a bug here -- I don't believe we ever construct a non-wf alias on the good path? If so, then we can just remove the delay.

Fixes #120891

r? lcnr

Author: matthiaskrgr