Update the QUIC packet format.

The QUIC packet format has changed again. Update the test to
ensure that the GFE can drop support for the old packet format
without causing all devices to fail CTS.

Packet format changes suggested by dschinazi@.

Test: atest --rerun-until-failure 100 CtsNetTestCasesLatestSdk:MultinetworkApiTest#testNativeDatagramTransmission
Change-Id: I8625ac9a58c55fc19dfb9fdb5f34a89cee40caaf
1 file changed