Add proper unit test to adbd_auth native API

This CL adds two emulation systems.

1. The Unix Domain Socket normaly created by init.
2. Framework's AdbDebuggingManager which opens the
  UDS, recv and send messages on it.

This allows to test the full adbauth pipeline. To
keep the volume of code low, this CL only improves
"TP" test but more tests will be added here.

Bug: NA
Test: adbd_auth_test
Flag: EXEMPT (tests)
Change-Id: I39d6f7abe2c6f3576c3d6786e38f3668ff10855f