Bug 1070845 - [sharedtest] unit test refactoring for new version chai.assert api

test_agent used very old version chai library version=0.5.3
in the current version=1.9.1 deepEqual take prototype into consideration
I'm quite confused here. The existing test clearly does not match the implentation. So I don't understand why it was succeeding.  Maybe assert.throws() is treating the return of a rejected promise to be a "throw"?

But I think that the proposed alternative test is not okay, either:

1) You're dropping the strings that identify the test cases. So if one of these tests fails, there won't be a string specifying which one.

2) The tests don't fail correctly. We're testing that all of these bad inputs cause the promise to be rejected. But there is no failure if the promise resolves.

3) The done() function may be called synchronously even though the function being tested is async.

4) The first two tests will not fail with "invalid output dimensions" because they're testing a bad blob, not bad dimensions.