Ass some unit tests to check if the minadbd service exit correctly in
the failure case. Also start the fuse and verify the socket communication
between minadbd with adb host, and minadbd with recovery.
Bug: 131037235
Test: run unit tests repeatedly, injects some errors and test fails
without dangling process.
Change-Id: I2f073b701b25d7f1aafc59868a7a91a8cbefaf49