[es6] Initial support for let/const bindings in sloppy mode

test/mjsunit/es6/block-leave.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 157 matching lines @@
     } finally {
       assertEquals('outer', eval('x'));
     }
   })('outer');
 } catch (e) {
   if (e instanceof MjsUnitAssertionError) throw e;
 }
 
 
 // Verify that the context is correctly set in the stack frame after exiting
-// from with.
+// from eval.
 function f() {}
 
 (function(x) {
   label: {
     let x = 'inner';
     break label;
   }
   f();  // The context could be restored from the stack after the call.
   assertEquals('outer', eval('x'));
 })('outer');
@@ skipping 26 matching lines @@
       let x = 'inner';
       throw 0;
     } finally {
       f();
       assertEquals('outer', eval('x'));
     }
   })('outer');
 } catch (e) {
   if (e instanceof MjsUnitAssertionError) throw e;
 }