In the Tor case, this prevents us from telling the Tor daemon to send
our incoming connections from the Tor network to an address where we
do not listen (we tried to listen but failed probably because another
application is already listening).
In the other cases (IPv4/IPv6 binds) this also prevents unpleasant
surprises caused by continuing operations even on bind failure. For
example, another application may be listening on portX, bitcoind tries
to bind on portX and portY, only succeeds with portY and continues
operation leaving the user thinking that his bitcoind is listening on
portX whereas another application is listening (the error message in
the log could easily be missed).
Avoid having the functional testing framework start multiple `bitcoind`s
that try to listen on the same `127.0.0.1:18445` (Tor listen for
regtest) if `bind_to_localhost_only` is set to `False`.
Also fix a typo in `test-shell.md` related to `bind_to_localhost_only`.
Fixes https://github.com/bitcoin/bitcoin/issues/22727
Tackles two issues in the TestShell documentation:
- add missing instruction for creating a wallet prior to the
`getnewaddress` call (needed as there is no default wallet created
anymore since v0.21)
- fix `generatetoaddress` call syntax (the scripted-diff in commit
fa0b916971 only worked for tests using
`BitcoinTestFramework`)
