Fix authority parsing test

The test has been failing because http://r.android.com/793302 changed
how the port separator was found, only scanning ASCII digits until it
hits a colon, and previously it would scan for the colon and then
percent-decode the rest of it.  The new behavior actually better
matches the WHATWG URL parsing algorithm [1], which specifies that
ports only include ASCII digits.  It does mean that some edge cases
that previously parsed as host "foo", port 42 will now parse as
host "foo:42", no port, but those URLs wouldn't be accepted by
browsers so they should be exceedingly rare.

The behavior per the WHATWG spec would be to fail to parse in the case
of a percent-encoded character in the port section, but this class is
specifically documented to accept garbage, so lumping the mis-encoded
port as part of the hostname (which will result in a hostname that's
invalid and impossible to resolve) seems like the best option.

[1] https://url.spec.whatwg.org/#port-state

Fixes: 124360078
Test: atest android.net.UriTest
Change-Id: I1c788cb7703c821ae74b542b74d89e10cba5a546