Auto merge of #122077 - oli-obk:eager_opaque_checks4, r=lcnr

Pass list of defineable opaque types into canonical queries

This eliminates `DefiningAnchor::Bubble` for good and brings the old solver closer to the new one wrt cycles and nested obligations. At that point the difference between `DefiningAnchor::Bind([])` and `DefiningAnchor::Error` was academic. We only used the difference for some sanity checks, which actually had to be worked around in places, so I just removed `DefiningAnchor` entirely and just stored the list of opaques that may be defined.

fixes #108498
fixes rust-lang/rust#116877

* [x] run crater
  - rust-lang/rust#122077 (comment)

Author: bors