message: test(debounceTime): fix VirtualTimeScheduler location
diff: import { expect } from 'chai';
  import * as Rx from '../../src/Rx';
  import marbleTestingSignature = require('../helpers/marble-testing'); // tslint:disable-line:no-require-imports
  -import { VirtualTimeScheduler } from '../../src/scheduler/VirtualTimeScheduler';
  +import { VirtualTimeScheduler } from '../../src/internal/scheduler/VirtualTimeScheduler';
  declare const { asDiagram };
  declare const hot: typeof marbleTestingSignature.hot;
  