Url::getHostUrl() returns scheme only when host is '0'

[spaze]

Version: master (3.0.1)

Bug Description

$url->getHostUrl() returns just scheme when the host is 0.

$url = new Url('https://0/0');
$url->getHostUrl();  // https:

Steps To Reproduce

This is a failing test

$url = new Url('https://0/0');
Assert::same('https://0', $url->getHostUrl());

Expected Behavior

The host (0) should be included.

Possible Solution

I'll send a PR in a second.