Allow SDM's web server to reuse a socket without waiting (#9946)

This is Jetty's default for a Connector, and reflects the configuration
used by the DevMode Jetty app server instance.

Fixes #9944

dev/codeserver/java/com/google/gwt/dev/codeserver/WebServer.java

@@ -121,7 +121,7 @@ void start(final TreeLogger logger) throws UnableToCompleteException {
     ServerConnector connector = new ServerConnector(newServer);
     connector.setHost(bindAddress);
     connector.setPort(port);
-    connector.setReuseAddress(false);
+    connector.setReuseAddress(true);
     newServer.addConnector(connector);
 
     ServletContextHandler newHandler = new ServletContextHandler(ServletContextHandler.GZIP);