Defer creating Handles for HConstants to the code generation phase.

src/x64/lithium-x64.cc

Index: src/x64/lithium-x64.cc
diff --git a/src/x64/lithium-x64.cc b/src/x64/lithium-x64.cc
index 642e951ccde7e49b1fb9ba880c5845f4cfa9a5b3..dec0e983fb61d83abd5fa15bf294ce83d8c3cbc7 100644
--- a/src/x64/lithium-x64.cc
+++ b/src/x64/lithium-x64.cc
@@ -527,8 +527,8 @@ void LChunk::AddGapMove(int index, LOperand* from, LOperand* to) {
 }
 
 
-Handle<Object> LChunk::LookupLiteral(LConstantOperand* operand) const {
-  return HConstant::cast(graph_->LookupValue(operand->index()))->handle();
+HConstant* LChunk::LookupLiteral(LConstantOperand* operand) const {
+  return HConstant::cast(graph_->LookupValue(operand->index()));
 }