Remove harmony-atomics flag and collapse it into sharedarraybuffer flag

test/mjsunit/regress/regress-crbug-501809.js

Index: test/mjsunit/regress/regress-crbug-501809.js
diff --git a/test/mjsunit/regress/regress-crbug-501809.js b/test/mjsunit/regress/regress-crbug-501809.js
index c3abadfab54e47bd22b47f374738fed29c30df96..855b36a054627d3be0918230f748ac5f9c471ad1 100644
--- a/test/mjsunit/regress/regress-crbug-501809.js
+++ b/test/mjsunit/regress/regress-crbug-501809.js
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// Flags: --harmony-sharedarraybuffer --harmony-atomics
+// Flags: --harmony-sharedarraybuffer
 var sab = new SharedArrayBuffer(8);
 var ta = new Int32Array(sab);
 ta.__defineSetter__('length', function() {;});