`RouterInfo` reports empty string as zero-th subdomain for domains with no subdomain(s)

[T99]

When using this domain:

localhost:1711

The following RoutingInfo is generated:

{
	"url": "http://localhost:1711/",
	"topLevelDomain": "localhost",
	"domainName": "localhost",
	"subdomainComponents": [""],
	"subdomainComponentsIndex": 0,
	"pathComponents": [],
	"pathComponentsIndex": 0,
	"doesHaveTrailingSlash": true,
	"routingParameters": {}
}

...which incorrectly lists a single subdomain - the empty string.