Deserializing many TypeReps may lead to high residency

Deserialized `TypeRep`s don't share any structure with each other, which can potentially waste a lot of space. For example, if I fill a giant `Set` with deserialized `Dynamic` values, the lion's share of the space could be taken up by the `TypeRep`s. One potential fix would be to maintain weak tables holding deserialized `TyCon`s and `TypeRep`s. We could use one of type `Map Fingerprint (exists a. Weak (TypeRep a))` and one of type `Map Fingerprint (Weak TyCon)`, but other sorts of maps would probably be faster. When a (perhaps recursively) deserialized `TyCon` or `TypeRep` matches one stored in the table, it would be thrown away in favor of the stored one.

Empieza rastreando cómo se deserializan los valores TypeRep y TyCon y cómo los fingerprints los identifican; el issue no menciona archivos ni tests. Investiga opciones de tablas débiles para compartir valores deserializados recursivamente y, después, define mediciones que demuestren una menor ocupación de memoria cuando se cargan muchos valores Dynamic, preservando al mismo tiempo el comportamiento de deserialización.

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