Fix WebBluetooth generator to distinguish between different methods.

third_party/WebKit/LayoutTests/bluetooth/script-tests/service/disconnect-invalidates-objects.js

 'use strict';
 promise_test(() => {
   return setBluetoothFakeAdapter('DisconnectingHealthThermometerAdapter')
     .then(() => requestDeviceWithKeyDown({
       filters: [{services: ['health_thermometer']}],
       optionalServices: [request_disconnection_service_uuid]}))
     .then(device => device.gatt.connect())
     .then(gattServer => {
       return gattServer.getPrimaryService('health_thermometer')
         .then(service => service.CALLS([
@@ skipping 29 matching lines @@
             error));
         promises = promises.then(() =>
           assert_promise_rejects_with_message(
             characteristic.stopNotifications(),
             error));
       }
       return promises;
     });
 }, 'Calls on characteristics after we disconnects and connect again. ' +
    'Should reject with InvalidStateError.');