Auto merge of rust-lang#157374 - khyperia:remove-UnevaluatedConstKind-def_id, r=BoxyUwU

remove UnevaluatedConstKind::def_id

this is some of the const side of rust-lang#152245

not quite a _full_ removal, there's still some spicy things such as `UnevaluatedConstKind::def_span` remaining that won't quite work for new non-DefID `UnevaluatedConstKind` cases, but IMO this is the bulk of the work, and feature-specific things can deal with their quirks in their own PRs when they know their own use cases.

r? @BoxyUwU 

self-reminder: file an issue on what to do about rustc_public's handling of the raw DefIds in rustc_public AliasTy/AliasConst

Author: bors