Add test for importing via descriptor
Add test for importing via descriptor

Summary:
This is a partial backport of Core [[https://github.com/bitcoin/bitcoin/pull/14491 | PR14491]] : https://github.com/bitcoin/bitcoin/pull/14491/commits/fbb5e935eaf17d603ec62e1a704a174235540b71

Depends on D6187 and D6191

Test Plan:
  ninja all check-all

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D6192

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