Flush SWD queue when resuming a target
Flush SWD queue when resuming a target

This resolves issues with non consistency between pyOCD and GDB states when GDB assumes target is running but in fact it is not

mbedmicro/pyOCD,mbedmicro/pyOCD,mbedmicro/pyOCD,pyocd/pyOCD,pyocd/pyOCD,mesheven/pyOCD,mesheven/pyOCD,flit/pyOCD,mesheven/pyOCD,flit/pyOCD