test_resource: cover setting shots and memory options

[airwoodix]

Summary

This patch adds tests for setting the shots and memory execution options on the offline simulators. This partially also covers the case of remote devices.

Details and comments

Checked cases are:

• set the option in Backend.run
• set the option in qiskit.execute
• set the option as global resource option
• set the option in Backend.run or qiskit.execute overrides the resource option.