Revert I+TF for lexical variables

src/ast/ast-numbering.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/ast/ast-numbering.h"
 
 #include "src/ast/ast.h"
 #include "src/ast/scopes.h"
 #include "src/compiler.h"
 #include "src/objects-inl.h"
@@ skipping 148 matching lines @@
     case VariableLocation::LOOKUP:
       DisableFullCodegenAndCrankshaft(
           kReferenceToAVariableWhichRequiresDynamicLookup);
       break;
     case VariableLocation::MODULE:
       DisableFullCodegenAndCrankshaft(kReferenceToModuleVariable);
       break;
     default:
       break;
   }
-  if (node->var()->binding_needs_init()) {
-    // Disable FCG+CS for all variable bindings that need explicit
-    // initialization, i.e. ES2015 style const and let, but not
-    // named function expressions.
-    DisableFullCodegenAndCrankshaft(kReferenceToLetOrConstVariable);
-  }
   node->set_base_id(ReserveIdRange(VariableProxy::num_ids()));
 }
 
 
 void AstNumberingVisitor::VisitVariableProxy(VariableProxy* node) {
   VisitVariableProxyReference(node);
   ReserveFeedbackSlots(node);
 }
 
 
@@ skipping 478 matching lines @@
     Compiler::EagerInnerFunctionLiterals* eager_literals) {
   DisallowHeapAllocation no_allocation;
   DisallowHandleAllocation no_handles;
   DisallowHandleDereference no_deref;
 
   AstNumberingVisitor visitor(stack_limit, zone, eager_literals);
   return visitor.Renumber(function);
 }
 }  // namespace internal
 }  // namespace v8