Merge changes I6745a615,Ic50dc122,I38729c23,I6d1da4f1,I1cef6e09, ...

* changes:
  [CLATJ#16] Rename JNI/Dependencies function and improve JNI error handling
  [CLATJ#15] ClatCoordinator: add socket filter to packet socket
  [CLATJ#14] ClatCoordinator: add anycast to raw socket
  [CLATJ#13] ClatCoordinator: open raw socket
  [CLATJ#12] ClatCoordinator: open packet socket with a given mark
  [CLATJ#11] ClatCoordinator: config tun interface and bring up
  [CLATJ#10] ClatCoordinator: detect mtu
  [CLATJ#9] ClatCoordinator: open tun interface
  [CLATJ#8] ClatCoordinator: select IPv6 address with checksum-neutral IID
  [CLATJ#7] ClatCoordinator: select IPv4 address for clatd
  [CLATJ#6] libclat: move configure_packet_socket() from netd to apex
  [CLATJ#5] libclat: move detect_mtu() from netd to apex
  [CLATJ#4] libclat: move selectIpv4Address() and isIpv4AddressFree() from netd to apex
  [CLATJ#3] libclat: move generateIpv6Address() from netd to apex
  [CLATJ#2] libclat: Add libclat_test to postsubmit
  [CLATJ#1] libclat: move makeChecksumNeutral() from netd to apex