Pass a valid ZObject to makeWrappedResultEnvelope, not an Error.

I don't think this will fix the issue we see when trying to update the evaluator, but it should help us debug.

The only place I've been able to trigger the "Unserializable input: {}" error that we see when trying to update the JS WASM evaluator is in this line in src/execute.js, which is indeed problematic. Unfortunately, I was only able to trigger this case when the evaluator was also not functioning. I guess this is an issue with the retry logic, but it's not something I can easily write a test case for.

I have filed a task to write a unit test for this situation.