Fix issues with InputMapper tests

- When an input device is added, a device reset notification is sent.
  This should be consumed when the device is added so that it does
  not need to be consumed in every test case.
- The above change exposed an issue with a CursorInputMapper test case,
  where it was consuming the wrong device reset notification.
- When a device is configured, it may produce device reset
  notifications. After configuring, we should loop the input reader so
  that the queued input listener is flushed so that these args can be
  sent out.

Bug: None
Test: atest inputflinger_tests
Change-Id: Ic4979b91207a6abf4c4ac65fd3db30307cb53729