Implemented the RoundInt64ToFloat32 TurboFan operator for x64, arm64, and mips64.

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 5c7123da3d4fa372c098dd3dcd9a8c513c45b6ad..d4b8e93d100c79ceebc843ddad9fea75127d01d0 100644
--- a/src/compiler/raw-machine-assembler.h
+++ b/src/compiler/raw-machine-assembler.h
@@ -458,6 +458,9 @@ class RawMachineAssembler {
   Node* TruncateInt64ToInt32(Node* a) {
     return AddNode(machine()->TruncateInt64ToInt32(), a);
   }
+  Node* RoundInt64ToFloat32(Node* a) {
+    return AddNode(machine()->RoundInt64ToFloat32(), a);
+  }
   Node* RoundInt64ToFloat64(Node* a) {
     return AddNode(machine()->RoundInt64ToFloat64(), a);
   }