fix(ngMock.$interval): should use angular.isDefined

The newly introduced `$interval` mock service for ngMock calls `isDefined`
in the global namespace which fails when used within unit tests.

This change adds the missing `angular.` prefix to such `isDefined` calls.

Closes #4334
Closes #4353
feat(ngParse): support trailing commas in object & array literals

Per ECMAScript 5.1 specification trailing commas are allowed in object and
array literals. All modern browsers as well as IE>8 support this syntax.
This commit adds support for such syntax to Angular expressions.