891beb0 [test] fundrawtransaction: lock watch-only shared address (Karl-Johan Alm)
Pull request description:
`self.nodes` creates an address which is watch-only-shared with `self.nodes`. If `nodes` spends the associated UTXO during any of its sends later, the watchonly test will fail, as `nodes` 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).
Backport of Core PR12265