trie/bintrie: skip resolver for zero-hash children

[rizkyikiw42]

Skip resolver calls for zero-hash HashedNodes in binary trie internal nodes, treating them as Empty nodes instead. When InternalNodes with Empty children are serialized and deserialized, the Empty children become zero-hash HashedNodes that trigger unnecessary database lookups and fail with "not found" errors.

[gballet]

This change will not be applied because it is a low-impact cosmetic change. There is no difference in performance, and it doesn't meaningfully improve code quality.