Ensure closeTestServer is actually called in integration tests

Author: andreiborza

dev-packages/node-core-integration-tests/suites/tracing/requests/fetch-no-tracing-no-spans/test.ts

@@ -44,7 +44,7 @@ describe('outgoing fetch', () => {
         })
         .start()
         .completed();
-      closeTestServer;
+      closeTestServer();
     });
   });
 });

dev-packages/node-integration-tests/suites/tracing/requests/fetch-no-tracing-no-spans/test.ts

@@ -44,7 +44,7 @@ describe('outgoing fetch', () => {
         })
         .start()
         .completed();
-      closeTestServer;
+      closeTestServer();
     });
   });
 });