core::rt: Unignore a fixed TCP test

Author: brson

src/libcore/rt/io/net/tcp.rs

@@ -314,7 +314,7 @@ mod test {
         }
     }
 
-    #[test] #[ignore(reason = "hangs on mac")]
+    #[test]
     fn multiple_connect_interleaved_lazy_schedule() {
         do run_in_newsched_task {
             let addr = next_test_ip4();