Remove --harmony-async-await runtime flag

test/mjsunit/harmony/regress/regress-618603.js

Index: test/mjsunit/harmony/regress/regress-618603.js
diff --git a/test/mjsunit/harmony/regress/regress-618603.js b/test/mjsunit/harmony/regress/regress-618603.js
deleted file mode 100644
index 8f45cd88f081fc4e601ec9b7dbe417c3be8476e3..0000000000000000000000000000000000000000
--- a/test/mjsunit/harmony/regress/regress-618603.js
+++ /dev/null
@@ -1,14 +0,0 @@
-// Copyright 2016 the V8 project authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-// Flags: --harmony-async-await
-
-try {
-} catch(e) {; }
-function __f_7(expected, run) {
-  var __v_10 = run();
-};
-__f_7("[1,2,3]", () => (function() {
-      return (async () => {[...await arguments] })();
-      })());