[fullcodegen] Lift restriction on --debug-code flag.

src/full-codegen/x64/full-codegen-x64.cc

Index: src/full-codegen/x64/full-codegen-x64.cc
diff --git a/src/full-codegen/x64/full-codegen-x64.cc b/src/full-codegen/x64/full-codegen-x64.cc
index 4ed8c2b88961ab81fdaa5896d396893054a1966b..b442fc73f9d821eee7b26969c66753639c96431a 100644
--- a/src/full-codegen/x64/full-codegen-x64.cc
+++ b/src/full-codegen/x64/full-codegen-x64.cc
@@ -726,7 +726,7 @@ void FullCodeGenerator::PrepareForBailoutBeforeSplit(Expression* expr,
 void FullCodeGenerator::EmitDebugCheckDeclarationContext(Variable* variable) {
   // The variable in the declaration always resides in the current context.
   DCHECK_EQ(0, scope()->ContextChainLength(variable->scope()));
-  if (generate_debug_code_) {
+  if (FLAG_debug_code) {
     // Check that we're not inside a with or catch context.
     __ movp(rbx, FieldOperand(rsi, HeapObject::kMapOffset));
     __ CompareRoot(rbx, Heap::kWithContextMapRootIndex);
@@ -2339,7 +2339,7 @@ void FullCodeGenerator::EmitVariableAssignment(Variable* var, Token::Value op,
       // mode.
       DCHECK(var->IsStackAllocated() || var->IsContextSlot());
       MemOperand location = VarOperand(var, rcx);
-      if (generate_debug_code_ && var->mode() == LET && op == Token::INIT) {
+      if (FLAG_debug_code && var->mode() == LET && op == Token::INIT) {
         // Check for an uninitialized let binding.
         __ movp(rdx, location);
         __ CompareRoot(rdx, Heap::kTheHoleValueRootIndex);