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

test/mjsunit/harmony/block-let-declaration-sloppy.js

Index: test/mjsunit/harmony/block-let-declaration-sloppy.js
diff --git a/test/mjsunit/es6/block-let-declaration.js b/test/mjsunit/harmony/block-let-declaration-sloppy.js
similarity index 99%
copy from test/mjsunit/es6/block-let-declaration.js
copy to test/mjsunit/harmony/block-let-declaration-sloppy.js
index 5fbb12824b03657dd83191b3b2e4b255139cf6bb..e5913f8c08cdf89376f45cfed5af21313acfad67 100644
--- a/test/mjsunit/es6/block-let-declaration.js
+++ b/test/mjsunit/harmony/block-let-declaration-sloppy.js
@@ -27,7 +27,7 @@
 
 // Test let declarations in various settings.
 
-"use strict";
+// Flags: --no-legacy-const --harmony-sloppy
 
 // Global
 let x;