Add test for descriptor ranges in wallet_importmulti.py

Summary: This wasn't ported from PR14491 because it used segwit, but this can be done without segwit.

Test Plan:

ninja all check-all

Reviewers: #bitcoin_abc, majcosta

Reviewed By: #bitcoin_abc, majcosta

Subscribers: majcosta, PiRK

Differential Revision: https://reviews.bitcoinabc.org/D8359