Use an additional -bind flag instead of -port to specify the default p2p port.
Flag -port sets the default port number that will be used for any -bind or
-whitebind that does not explicitly specify a port. So if we have the p2p
port set in -port and the tor p2p port set in a single -bind, bitcoind binds
only one port - the tor p2p port. And the default p2p port remained not bound!
With this commit we create a new function that returns system wide
unique ports by using a single file to keep track of previously used
ports. We'll want to use this everywhere whenever we need to listen on a
new, random port during unit or integration tests.
Because we now have a unique source, we don't need to apply the port
offset that was used for the different tranches of parallel running
integration tests before.
With go 1.17 a change to the build flags was implemented:
https://go.googlesource.com/proposal/+/master/design/draft-gobuild.md
The formatter now automatically adds the forward-compatible build tag
format and the linter checks for them, so we need to include them in our
code.
