Fix generated tests for TS constructors

[jgaehring]

Originally posted by @jgaehring in #20 (comment)

I've got a start at the test generation (2c8507a). So far I'm just testing the constructor. There are a total of 109 tests with 99 passing and 10 failing. I've put the relevant tests and the full results up on this gist:

https://gist.github.com/jgaehring/bde27fe6991a289cc7016ed77bc1120e

There seem to be three kinds of errors that I'm not yet sure how to resolve:

1. Duplicate import statements, as in Enterprise.test.js, or missing imports, as in QuantitativeValue.test.js
2. Unknown ontology type in PlannedConsumptionFlow.test.js, which may be related to the Flow superclass or the ConnectorFactory, based on the stacktrace.
3. A weird issue where a plain string ends up as the test value for images in SuppliedProduct.test.js, which results in a images.forEach is not a function error, b/c it should be expecting an array of strings. The generated PHP tests also have a plain string for the images property, so maybe this is something to do with how the test values are generated?