fix: revert automatic server closing (per #651)

Author: titanism

lib/test.js

@@ -60,11 +60,10 @@ class Test extends Request {
   serverAddress(app, path) {
     const addr = app.address();
 
-    if (!addr) {
-      this._server = app.listen(0);
-    } else {
-      this._server = app;
-    }
+    if (!addr) this._server = app.listen(0);
+    // } else {
+    //   this._server = app;
+    // }
     const port = app.address().port;
     const protocol = app instanceof Server ? 'https' : 'http';
     return protocol + '://127.0.0.1:' + port + path;

test/supertest.js

@@ -1444,8 +1444,8 @@ describeHttp2('http2', function() {
             .end(function (err, res) {
               res.status.should.equal(200);
               res.text.should.equal('hey');
-              // Let supertest handle server closing
-              done();
+              // lose the external server explicitly
+              server.close(done);
             });
         });
       });