Ship ES2015 sloppy-mode const semantics

test/mjsunit/constant-folding.js

 // Copyright 2009 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
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 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 // Test operations that involve one or more constants.
 // The code generator now handles compile-time constants specially.
 // Test the code generated when operands are known at compile time
 
+// Flags: --legacy-const
+
 // Test count operations involving constants
 function test_count() {
   var x = "foo";
   var y = "3";
 
   x += x++;  // ++ and -- apply ToNumber to their operand, even for postfix.
   assertEquals(x, "fooNaN", "fooNaN test");
   x = "luft";
   x += ++x;
   assertEquals(x, "luftNaN", "luftNaN test");
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   x = 123;
   // Answer is non-smi and lhs of << is a temporary heap number that we think
   // we can overwrite (but we can't because it's a Smi).
   assertEquals(1073741824, (x * x) << 30);
 }
 
 
 test();
 BoolTest();
 ShiftTest();