Instantiation of N-qubit experiment data processor

[nkanazawa1989]

Informations

• Qiskit Experiments version:
• Python version:
• Operating system:

What is the current behavior?

#637 upgraded the instantiation of data processor so that it can automatically adjust the node to compute probability of N-qubit experiment. However, many 2Q experiments only measure the target qubit (e.g. Hamiltonian tomo, HEAT, most of CR calibrations except for ZI cal, thus this change will break these experiments.

Suggested solutions

Data processor should be instantiated based on number of cregs rather than one of physical qubits in the experiment.