Add build ICMPv6 echo request packet helper function in Ipv6Utils. am: 657b2e8660 am: 21839bcbdd

Original change: https://android-review.googlesource.com/c/platform/frameworks/libs/net/+/1669829

Change-Id: I74e2fab9a47dc0daf4d9a6ae8f406aecc6160eab
tree: a1c7cba490bae8a5e5f5d3864b5b6d89744b6ecd
  1. client-libs/
  2. common/
  3. .gitignore
  4. OWNERS
  5. PREUPLOAD.cfg
  6. TEST_MAPPING