[turbofan] Added the RoundInt64ToFloat64 instruction to TurboFan.

src/compiler/x87/instruction-selector-x87.cc

Index: src/compiler/x87/instruction-selector-x87.cc
diff --git a/src/compiler/x87/instruction-selector-x87.cc b/src/compiler/x87/instruction-selector-x87.cc
index a78bdb4b2849b5b56bee3828804a3d6cc015e02e..d58b00387599c396850e1480f2e6de0dde81b207 100644
--- a/src/compiler/x87/instruction-selector-x87.cc
+++ b/src/compiler/x87/instruction-selector-x87.cc
@@ -630,6 +630,11 @@ void InstructionSelector::VisitChangeInt32ToFloat64(Node* node) {
 }
 
 
+void InstructionSelector::VisitRoundInt64ToFloat64(Node* node) {
+  UNIMPLEMENTED();
+}
+
+
 void InstructionSelector::VisitChangeUint32ToFloat64(Node* node) {
   X87OperandGenerator g(this);
   Emit(kX87Uint32ToFloat64, g.DefineAsFixed(node, stX_0),