remove outdated test utils

test/utils/net-utils.ts

@@ -1,20 +0,0 @@
-import net from 'net';
-
-// using a free port instead of a constant port enables parallelization
-export function getFreePort() {
-  return new Promise((resolve, reject) => {
-    const server = net.createServer();
-    let port;
-    server.on('listening', function() {
-      port = (server.address() as any).port;
-      server.close();
-    });
-    server.on('close', function() {
-      resolve(port);
-    });
-    server.on('error', function(error) {
-      reject(error);
-    });
-    server.listen(0);
-  });
-}