Remove --harmony-async-await runtime flag

test/mjsunit/harmony/regress/regress-624300.js

Index: test/mjsunit/harmony/regress/regress-624300.js
diff --git a/test/mjsunit/harmony/regress/regress-624300.js b/test/mjsunit/harmony/regress/regress-624300.js
deleted file mode 100644
index f96fbbb5aaa1a22d4603e0c103372d1333af8f1a..0000000000000000000000000000000000000000
--- a/test/mjsunit/harmony/regress/regress-624300.js
+++ /dev/null
@@ -1,13 +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
-
-(function f() {
-  try {
-    f();
-  } catch (e) {
-    (async() => await 1).length;
-  }
-})();