[script] Unit tests for IsMine

Summary:
Does not test watch-only addresses.

This is partial backport of Core PR11116 : https://github.com/bitcoin/bitcoin/pull/11116/commits/7a1e873b27b790c965d9927ecd465710dc103136

Depends on D3116

Test Plan:

make check

Reviewers: #bitcoin_abc, markblundeberg

Reviewed By: #bitcoin_abc, markblundeberg

Subscribers: markblundeberg

Differential Revision: https://reviews.bitcoinabc.org/D3117