Fix WebBluetooth generator to distinguish between different methods.

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

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