Validate module.hot.accept(): Are all disposed modules reinstalled?

If I am not mistaken, a `module.hot.accept()` should re-install all disposed modules.

Otherwise, when a new hot-update arrives, it might bubble up to uninstalled parents and cause an error.

More info:

- [the error message](https://github.com/webpack/webpack/pull/479)
- [the original HMR dispose "bugfix" discussion](https://github.com/webpack/webpack/pull/468)