Execute the selftest and report the result.
PON: This does not execute any test, but simply evaluate the result of
the power on selftest,
NORMal: Execute the normal selftest (no need to disconnect DUT) and
report the result.
ALL: Execute the extended selftest and report the result. The instrument
must be completely disconnected from any external setup before the
extended selftest may be started.
The result is 0 if no errors are found and 1 if at least one test failed. The
error queue will contain the corresponding error messages.