Test Failure - Scene/Primitive shader validation

I'm seeing this in master on Chrome. @lilleyse @IanLilleyT, do you see this too?

```
Scene/Primitive shader validation
Expected function to throw DeveloperError.
Error: Expected function to throw DeveloperError.
at stack (http://localhost:8080/ThirdParty/jasmine-2.2.0/jasmine.js:1475:17)
at buildExpectationResult (http://localhost:8080/ThirdParty/jasmine-2.2.0/jasmine.js:1445:14)
at Spec.expectationResultFactory (http://localhost:8080/ThirdParty/jasmine-2.2.0/jasmine.js:584:18)
at Spec.addExpectationResult (http://localhost:8080/ThirdParty/jasmine-2.2.0/jasmine.js:332:34)
at Expectation.addExpectationResult (http://localhost:8080/ThirdParty/jasmine-2.2.0/jasmine.js:528:21)
at Expectation.toThrowDeveloperError (http://localhost:8080/ThirdParty/jasmine-2.2.0/jasmine.js:1399:12)
at http://localhost:8080/Specs/Scene/PrimitiveSpec.js:1175:12
at Object. (http://localhost:8080/Specs/spec-main.js:89:30)
at attemptAsync (http://localhost:8080/ThirdParty/jasmine-2.2.0/jasmine.js:1793:24)
at QueueRunner.run (http://localhost:8080/ThirdParty/jasmine-2.2.0/jasmine.js:1746:26)
```

Start with Specs/Scene/PrimitiveSpec.js around line 1175 and run the “Scene/Primitive shader validation” test in Chrome. Trace the failing expectation to determine why the function no longer throws DeveloperError. Done means the test's expected validation behavior is restored and the spec passes.

Written by the indexing model from the issue text.