Tracking Issue: Property testing

[doug-q]

We now have property testing using the [proptest](https://crates.io/crates/proptest) crate that all types in the serialisation schema can be retain equality after a serialisation -> deserialisation round trip.

• test: proptests for round trip serialisation of Types and Ops. #981
• test: serialisation round trip testing for OpDef #999

As it stands there are some limitations to our tests that inhibit it's utility:

• Property Testing: Generate valid values #1053
• Property Testing: test generator coverage #1054