Rollup merge of #143975 - RalfJung:type-id-eq, r=oli-obk

type_id_eq: check that the hash fully matches the type

The previous logic wouldn't always detect when the hash mismatches the provenance. Fix that by adding a new helper, `read_type_id`, that reads a single type ID while fully checking it for validity and consistency.

r? ``@oli-obk``

Author: matthiaskrgr