Support fake data generator in FakeVehicleHardware.

Support dump command 'genfakedata' in FakeVehicleHardware. Client
could use this command to generate fake events. This is used in
vehiclehal integration test.

Test: atest FakeVehicleHardwareTest
Bug: 199314530
Change-Id: Id7abcf289debe22f29f4299cc93417ac51bc1a3b
9 files changed