Additional memory and storage savings are possible by deduplicating Cadence dictionary type info

[fxamacker]

Updates #292, https://github.com/onflow/cadence/issues/1854, https://github.com/onflow/flow-go/issues/1744

I think we can deduplicate Cadence dictionary type info, which would further reduce total payload size.

PR #342 added atree inlining which makes data deduplication feasible. Same PR also added data deduplication for:

• Cadence array type info
• Cadence composite type info

After examining real data from mainnet, I think the savings can be worthwhile by deduplicating Cadence dictionary type info.

[fxamacker]

Closed by #369