Enable ES6 Map and Set by default

test/mjsunit/es6/regress/regress-2186.js

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
 //       with the distribution.
 //     * Neither the name of Google Inc. nor the names of its
 //       contributors may be used to endorse or promote products derived
 //       from this software without specific prior written permission.
 //
 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-// Flags: --harmony-collections
-
 function heapify(i) {
   return 2.0 * (i / 2);
 }
 heapify(1);
 
 var ONE = 1;
 var ANOTHER_ONE = heapify(ONE);
 assertSame(ONE, ANOTHER_ONE);
 assertEquals("number", typeof ONE);
 assertEquals("number", typeof ANOTHER_ONE);
 
 var set = new Set;
 set.add(ONE);
 assertTrue(set.has(ONE));
 assertTrue(set.has(ANOTHER_ONE));
 
 var map = new Map;
 map.set(ONE, 23);
 assertSame(23, map.get(ONE));
 assertSame(23, map.get(ANOTHER_ONE));