WebServer implementations should return -1 if not listening on a port #24606
Please note: Jetty itself does return -2 as the local port after the connection has been closed. Therefore in its implementation getPort() maps all local ports <= 0 to -1 to match the method's contract.
The interface org.springframework.boot.web.server.WebServer defines that getPort() returns -1 if the server isn't listening on a port. This commit changes the implementations of the interface accordingly. See gh-24540