scpi-dmm: avoid get/set range calls for some of the Agilent DMM functions

While queries for the range are supported for voltage, current,
resistence, capacitance, the same queries in temperature, frequency,
diode, continuity modes not only fail but even lose the USB connection
to the device. This was consistently observed with 34405A and 34465A.

Suppress get and set range requests for the known problematic modes of
the Agilent protocol speaking meters.