The idea is to have different default ports for different networks.
Current default port is `9735` for everything. Let's use it for
the mainnet and reuse the difference added to the default port
from `rpc_port` values in `bitcoin/chainstate.c`.
Testnet would be `19735` (adding rpc_port - 8332 = `10000`).
Signet would be `39735` (adding rpc_port - 8332 = `30000`).
Regtest would be `19846` (adding rpc_port - 8332 = `10111`).
With Vincenzo's kind pair-programming help over tmate.
Two other commits were squashed into this one so that bisecting
never ends up in half-baked state:
1. chainparams: Fix regtest default rpc_port
bitcoind -help says this:
-rpcport=<port>
Listen for JSON-RPC connections on <port> (default: 8332, testnet:
18332, signet: 38332, regtest: 18443)
2. test_gossip: Default port for regtest
hex: 2607 is now .... (could be 4d86 but Elements uses another port)
dec: 9735 is now any port (could be 19846 ^^ but now is for any port)
The lines which were binding to default port were removed as the
default port is different on each network.
NOTE: Remember not to modify gossip_store tests which loads everything raw
including the checksums.
Changelog-Changed: If the port is unspecified, the default port is chosen according to used network similarly to Bitcoin Core.