the variable successResponses' s value /^0|([123]\d\d)|(40[14567])|410$/ is wrong for 404

[tangpo]

in fetchAndCache method , when the fetch method return response Object that the status is 404, the successResponses.test(response.status) is also return true.

Is this a bug?

中文版：fetchAndCache方法里面，当通过fetch方法获取一个不存在的文件，即返回404状态码时，这语句request.method === 'GET' && successResponses.test(response.status) 也校验通过，把404 都当成成功响应，请问这个是不是bug。