test: Add explicit onion bind to p2p_permissions

Summary:
When the bind option is replaced in the bitcoin.conf, bitcoind will
attempd to bind to the default tor listening port. If another bitcoind
is running that is already bound to that port, the bind will fail which,
since D17662, causes the test to fail.

This failure can be avoided by explicitly binding the tor port when the
bind is removed.

This is a backport of core#30805

Note missing refactors: core#28392, core#26956

Test Plan: ninja check-functional

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D17673