flash_test.py doesn't raise if performance info is None.
flash_test.py doesn't raise if performance info is None.

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