HostsFileNameService doesn't handle IPv6 literal addresses correctly

For example, ::1 and 0:0:0:0:0:0:0:1 should yield the same output.

The system property `jdk.net.hosts.file` can be defined to effect InetAddress name and address resolution calls, i.e getByXXX. The value of the system property is a filename that contains the mappings. The structure of this file is equivalent to that of the /etc/hosts file.

For example:
  10.2.3.4 testHost.testDomain
  ::1 ip6-localhost ip6-loopback