[turbofan] Make an OptionalOperator for MachineOperatorBuilder.

src/compiler/raw-machine-assembler.h

Index: src/compiler/raw-machine-assembler.h
diff --git a/src/compiler/raw-machine-assembler.h b/src/compiler/raw-machine-assembler.h
index b33836802489dcdb7639fb79ccb31063c41845de..ee81dba03f8ba2883753270c97aa86d1f819293d 100644
--- a/src/compiler/raw-machine-assembler.h
+++ b/src/compiler/raw-machine-assembler.h
@@ -340,7 +340,7 @@ class RawMachineAssembler : public GraphBuilder {
   Node* Float32Div(Node* a, Node* b) {
     return NewNode(machine()->Float32Div(), a, b);
   }
-  Node* Float32Abs(Node* a) { return NewNode(machine()->Float32Abs(), a); }
+  Node* Float32Abs(Node* a) { return NewNode(machine()->Float32Abs().op(), a); }
   Node* Float32Sqrt(Node* a) { return NewNode(machine()->Float32Sqrt(), a); }
   Node* Float32Equal(Node* a, Node* b) {
     return NewNode(machine()->Float32Equal(), a, b);
@@ -374,7 +374,7 @@ class RawMachineAssembler : public GraphBuilder {
   Node* Float64Mod(Node* a, Node* b) {
     return NewNode(machine()->Float64Mod(), a, b);
   }
-  Node* Float64Abs(Node* a) { return NewNode(machine()->Float64Abs(), a); }
+  Node* Float64Abs(Node* a) { return NewNode(machine()->Float64Abs().op(), a); }
   Node* Float64Sqrt(Node* a) { return NewNode(machine()->Float64Sqrt(), a); }
   Node* Float64Equal(Node* a, Node* b) {
     return NewNode(machine()->Float64Equal(), a, b);
@@ -425,13 +425,13 @@ class RawMachineAssembler : public GraphBuilder {
     return NewNode(machine()->TruncateInt64ToInt32(), a);
   }
   Node* Float64RoundDown(Node* a) {
-    return NewNode(machine()->Float64RoundDown(), a);
+    return NewNode(machine()->Float64RoundDown().op(), a);
   }
   Node* Float64RoundTruncate(Node* a) {
-    return NewNode(machine()->Float64RoundTruncate(), a);
+    return NewNode(machine()->Float64RoundTruncate().op(), a);
   }
   Node* Float64RoundTiesAway(Node* a) {
-    return NewNode(machine()->Float64RoundTiesAway(), a);
+    return NewNode(machine()->Float64RoundTiesAway().op(), a);
   }
 
   // Float64 bit operations.