byte_profile was failing on systems where fp_ops is a derived event.
byte_profile was failing on systems where fp_ops is a derived event.

modify the test so it gives a warning instead of failing and avoids
  using the derived event.

pyrovski/papi,pyrovski/papi,arm-hpc/papi,arm-hpc/papi,arm-hpc/papi,pyrovski/papi,pyrovski/papi,arm-hpc/papi,pyrovski/papi,pyrovski/papi,arm-hpc/papi,arm-hpc/papi,arm-hpc/papi,pyrovski/papi,pyrovski/papi