[CTS] Make sure the device  is awake and unlocked before running tests

Recently some tests relying on UI automation were failing on  cuttlefish
due to the device not being unlocked before the test. It can be caused
by an unexpected reboot or another test leaving the device in locked
state.

This CL makes sure we wake up and unlock the device before each test.

Bug: 181802051
Test: atest CtsBackupHostTestCases
Change-Id: If98c2a8ed7c0c12feec89c5ec6060c894e6f8826