This bumps the timeout to match Core since it appears to be flaky on CI: https://build.bitcoinabc.org/project.html?projectId=BitcoinABC_ResourceIntensiveBuilds&testNameId=7256257418448933135&tab=testDetails

Partial backport of Core PR16888 (most of it is already backported, minus the tests we do not have yet)

I can't reproduce the flakiness on my machine, but regardless I ran this a few times:

test_runner.py tool_wallet