This is a no-op refactoring, which is preparation for follow-up
changes to add more apf test classes.
This includes:
1. Move initialization code to a base class, which setup a hotspot
and a client connects to it, and enable doze mode to
activate the apf.
2. Check whether send raw packet is supported before testing.
Test: m connectivity_multi_devices_snippet && \
atest CtsConnectivityMultiDevicesTestCases
Test: atest NetworkStaticLibHostPythonTests
Bug: 350880989
Change-Id: I6376935883653182728e473e2f5533407d993d7b
cf655869ba