[turbofan] Initial support for monomorphic/polymorphic property loads.

test/mjsunit/es6/block-scoping.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 72 matching lines @@
     assertEquals(4, z);
     assertEquals(5, u);
     assertEquals(6, v);
     assertEquals(7, a.foo());
     assertEquals(8, b.foo());
   }
 }
 for (var j = 0; j < 5; ++j) f3(1);
 %OptimizeFunctionOnNextCall(f3);
 f3(1);
-assertTrue(%GetOptimizationStatus(f3) != 2);
 
 
 
 // Dynamic lookup from closure.
 function f4(one) {
   var x = one + 1;
   let y = one + 2;
   const u = one + 4;
   class a { static foo() { return one + 6; } }
   {
@@ skipping 199 matching lines @@
   }
   for (var j = 0; j < 10; j++) {
     y = j + 10;
     assertEquals(j, let_accessors[j]());
     assertEquals(y, var_accessors[j]());
     assertEquals(j, const_accessors[j]());
     assertEquals(j, class_accessors[j]().foo());
   }
 }
 f8();