Why have cortex_handlers.c?

Yup, but we are not talking about removing handlers, but about cleaning-up some handlers that was defined as a non-weak functions that does nothing! see the example posted by fat16lib:

void SVC_Handler( void )
{
  for ( ;; ) ;
}

this was due to some testing code coming from the beta-testing period and not cleaned up. But I'm pretty sure I've already fixed upstream.