Drop obsolete ES6 TODOs about activating extended mode.

test/mjsunit/harmony/debug-evaluate-blockscopes.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: --expose-debug-as debug --harmony-scoping
 
 // Test debug evaluation for functions without local context, but with
 // nested catch contexts.
 
-// TODO(ES6): properly activate extended mode
 "use strict";
 
 var x;
 var result;
 
 function f() {
   {                   // Line 1.
     let i = 1;        // Line 2.
     try {             // Line 3.
       throw 'stuff';  // Line 4.
@@ skipping 17 matching lines @@
 // Add the debug event listener.
 Debug.setListener(listener);
 result = -1;
 f();
 assertEquals(1, result);
 
 // Clear breakpoint.
 Debug.clearBreakPoint(bp);
 // Get rid of the debug event listener.
 Debug.setListener(null);