[js] Update a test to only check the error type, as the error message will

differ by driver implementation

Author: jleyba

javascript/node/selenium-webdriver/test/execute_script_test.js

@@ -343,8 +343,6 @@ test.suite(function(env) {
             fail('it should have timed out');
           }).catch(function(e) {
             assert(e.name).equalTo('ScriptTimeoutError');
-            assert(e.message).contains('Timed out waiting for async script \
-result after');
           });
       });