Updated unit tests to include test for array of valid audiences
Updated unit tests to include test for array of valid audiences

googleapis/google-auth-library-nodejs,JustinBeckwith/google-auth-library-nodejs,JustinBeckwith/google-auth-library-nodejs,JustinBeckwith/google-auth-library-nodejs,googleapis/google-auth-library-nodejs,JustinBeckwith/google-auth-library-nodejs