Include harmony-string-padding.js in the context snapshot

test/mjsunit/harmony/harmony-string-pad-start.js

Index: test/mjsunit/harmony/harmony-string-pad-start.js
diff --git a/test/mjsunit/harmony/harmony-string-pad-start.js b/test/mjsunit/harmony/harmony-string-pad-start.js
index 33bf8f3c9d5c11a7139c7012a3e69113cb370eed..5e1c36b949db10e0890a0834e2ad6b9c8bcd8b12 100644
--- a/test/mjsunit/harmony/harmony-string-pad-start.js
+++ b/test/mjsunit/harmony/harmony-string-pad-start.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// Flags: --harmony-string-padding
-
 (function TestMeta() {
   assertEquals(1, String.prototype.padStart.length);
   assertEquals("function", typeof String.prototype.padStart);