Fix Os.inet_pton for IPv6.

Native code assumed that the address offsets inside
struct sockaddr_storage were the same for both IPv4 and IPv6
which is not true on Android or Linux.

Bug: 123499570
Test: atest CtsLibcoreTestCases:libcore.libcore.io.OsTest
Change-Id: I40711a9c681fea75a8c2047a4d504b6cbdff0a47
2 files changed