Drop obsolete ES6 TODOs about activating extended mode.

test/mjsunit/harmony/block-const-assign.js

 // Copyright 2011 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
@@ skipping 12 matching lines @@
 // 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.
 
 // Flags: --harmony-scoping
 
 // Test that we throw early syntax errors in harmony mode
 // when using an immutable binding in an assigment or with
 // prefix/postfix decrement/increment operators.
-// TODO(ES6): properly activate extended mode
+
 "use strict";
 
-
 // Function local const.
 function constDecl0(use) {
   return "(function() { const constvar = 1; " + use + "; });";
 }
 
 
 function constDecl1(use) {
   return "(function() { " + use + "; const constvar = 1; });";
 }
 
@@ skipping 75 matching lines @@
     return;
   }
   assertUnreachable();
 }
 
 for (var d = 0; d < decls.length; ++d) {
   for (var u = 0; u < uses.length; ++u) {
     Test(decls[d], uses[u]);
   }
 }