Move Bluetooth remove service record handler to the app main thread

Move Bluetooth remove service record handler to the app main thread.
This removes the dependency of caller thread that constructs the
BluetoothAdapter singleton instance. The caller thread could stop while
BluetoothAdapter singleton exists but lose the handler context.
Make the BluetoothService.removeServiceRecord return quickly without
blocking on native call.
bug 4999443

Change-Id: I302534baa381f4aca8192e1e4a9ea21793b07ba6