Fix WebBluetooth generator to distinguish between different methods.

third_party/WebKit/LayoutTests/bluetooth/script-tests/service-get-same-object.js

-'use strict';
-promise_test(() => {
-  return setBluetoothFakeAdapter('TwoHeartRateServicesAdapter')
-    .then(() => requestDeviceWithKeyDown({
-      filters: [{services: ['heart_rate']}],
-      optionalServices: ['generic_access']}))
-    .then(device => device.gatt.connect())
-    .then(gattServer => Promise.all([
-      gattServer.CALLS([
-        getPrimaryService('heart_rate')|
-        getPrimaryServices()|
-        getPrimaryServices('heart_rate')[UUID]]),
-      gattServer.PREVIOUS_CALL]))
-    .then(services_arrays => {
-      // Convert to arrays if necessary.
-      for (let i = 0; i < services_arrays.length; i++) {
-        services_arrays[i] = [].concat(services_arrays[i]);
-      }
-
-      for (let i = 1; i < services_arrays.length; i++) {
-        assert_equals(services_arrays[0].length, services_arrays[i].length);
-      }
-
-      let base_set = new Set(services_arrays[0]);
-      for (let services of services_arrays) {
-        services.forEach(service => assert_true(base_set.has(service)));
-      }
-    });
-}, 'Calls to FUNCTION_NAME should return the same object.');