[turbofan] do not emit 2 operations for int64 add with overflow

src/compiler/x64/instruction-selector-x64.cc

Index: src/compiler/x64/instruction-selector-x64.cc
diff --git a/src/compiler/x64/instruction-selector-x64.cc b/src/compiler/x64/instruction-selector-x64.cc
index 41208bedb4d203e35a0e790212703984c973cc09..731ffde1904904a0b8384f9f0a4ef5a2fdd1dac5 100644
--- a/src/compiler/x64/instruction-selector-x64.cc
+++ b/src/compiler/x64/instruction-selector-x64.cc
@@ -690,7 +690,7 @@ void InstructionSelector::VisitInt64Add(Node* node) {
 void InstructionSelector::VisitInt64AddWithOverflow(Node* node) {
   if (Node* ovf = NodeProperties::FindProjection(node, 1)) {
     FlagsContinuation cont = FlagsContinuation::ForSet(kOverflow, ovf);
-    VisitBinop(this, node, kX64Add, &cont);
+    return VisitBinop(this, node, kX64Add, &cont);
   }
   FlagsContinuation cont;
   VisitBinop(this, node, kX64Add, &cont);