Crash when get TCPInfo under hostinet

[tanjianfeng]

Below command under hostinet network will lead to panic:

  $ cat /proc/net/tcp

It's caused by the wrong size of TCPInfo.

  #0 runtime.panicindex()
  #1 encoding/binary.littleEndian.Uint64
  #2 encoding/binary.(*littleEndian).Uint64
  #3 gvisor.dev/gvisor/pkg/binary.unmarshal
  #4 gvisor.dev/gvisor/pkg/binary.unmarshal
  #5 gvisor.dev/gvisor/pkg/binary.Unmarshal
  #6 gvisor.dev/gvisor/pkg/sentry/socket/hostinet.(*socketOperations).State
  #7 gvisor.dev/gvisor/pkg/sentry/fs/proc.(*netTCP).ReadSeqFileData

After initial investigation, we think the root cause is the wrong value of SizeOfTCPInfo (shall be 192 instead of 104).

[mrahatm]

Fixed by 691c2f8