Merge #12265: [test] fundrawtransaction: lock watch-only shared address

Summary:
891beb0 [test] fundrawtransaction: lock watch-only shared address (Karl-Johan Alm)

Pull request description:

`self.nodes[0]` creates an address which is watch-only-shared with `self.nodes[3]`. If `nodes[0]` spends the associated UTXO during any of its sends later, the watchonly test will fail, as `nodes[3]` now has insufficient funds.

I ran into this in #12257 and this commit is in that PR as well, but I figured I'd split it out (and remove from there once/if merged).

Tree-SHA512: d04a04b1ecebe82127cccd47c1b3de311bf07f4b51dff80db20ea2f142e1d5c4a85ed6180c5c0b081d550e238c742e119b953f60f487deac5a3f3536e1a8d9fe

Backport of Core PR12265
https://github.com/bitcoin/bitcoin/pull/12265/

Test Plan:

test_runner.py

Reviewers: deadalnix, Fabien, jasonbcox, O1 Bitcoin ABC, #bitcoin_abc

Reviewed By: deadalnix, O1 Bitcoin ABC, #bitcoin_abc

Differential Revision: https://reviews.bitcoinabc.org/D4153