Round-trip tests for Engine toString functions of Primitives.

[JPercival]

The output of engine toString functions for primitives should be identical to the CQL literal for the same type. We should add tests to verify and enforce that.

Example:

CQL for Interval Parameter:
parameter "Measurement Period" Interval
default Interval[@2019-01-01T00:00:00.0, @2020-01-01T00:00:00.0)

The output for the toString of that default interval should be:
"Interval[@2019-01-01T00:00:00.0, @2020-01-01T00:00:00.0)"

Same applies for the Tuple, Quantity, etc.