Auto merge of #113471 - compiler-errors:new-solver-norm-escaping, r=lcnr

Allow escaping bound vars during `normalize_erasing_regions` in new solver

Add `AllowEscapingBoundVars` to `deeply_normalize`, and use it in the new solver in the `query_normalize` routine.

Ideally, we'd make all `query_normalize` calls handle pass in `AllowEscapingBoundVars` individually, because really the only `query_normalize` call that needs `AllowEscapingBoundVars::Yes` is the one in `try_normalize_generic_arg_after_erasing_regions`, but I think that's kind of overkill. I am happy to be convinced otherwise, though.

r? `@lcnr`