make testdrive log message less verbose

1. Use custom TestDriveFormatter for log output.
It should be easy to fine tune it from here.
2. Fine tune logging level

Now the output looks like this:

./out/host/linux-x86/bin/statsd_testdrive 10
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by com.google.protobuf.Utf8$UnsafeProcessor (file:/android2/master/out/host/linux-x86/framework/statsd_testdrive.jar) to field java.nio.Buffer.address
WARNING: Please consider reporting this to the maintainers of com.google.protobuf.Utf8$UnsafeProcessor
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release
Pushed the following config to statsd:
id: 12345
event_metric {
  id: 1111
  what: 1234567
}
atom_matcher {
  id: 1234567
  simple_atom_matcher {
    atom_id: 10
  }
}

......

hash_strings_in_metric_report: false

Now please play with the device to trigger the event. All events should be dumped after 1 min ...
Success!
Got following metric data dump:
metric_id: 1111
event_metrics {
  data {

.....

        state: RELEASE
      }
    }
  }
}

Test: manual test
Change-Id: I9fcb09bbd1663f0eae85d428ed45a3b139f62782