[builtins] Introduce proper Float64Atan and Float64Atan2 operators.

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 878864f53178cf0b1a2e6ed821e8511a14edcfe3..aba5384298e164697c67ab51bebed34565e48bd6 100644
--- a/src/compiler/raw-machine-assembler.h
+++ b/src/compiler/raw-machine-assembler.h
@@ -460,6 +460,10 @@ class RawMachineAssembler {
   }
   Node* Float64Abs(Node* a) { return AddNode(machine()->Float64Abs(), a); }
   Node* Float64Neg(Node* a) { return Float64Sub(Float64Constant(-0.0), a); }
+  Node* Float64Atan(Node* a) { return AddNode(machine()->Float64Atan(), a); }
+  Node* Float64Atan2(Node* a, Node* b) {
+    return AddNode(machine()->Float64Atan2(), a, b);
+  }
   Node* Float64Log(Node* a) { return AddNode(machine()->Float64Log(), a); }
   Node* Float64Log1p(Node* a) { return AddNode(machine()->Float64Log1p(), a); }
   Node* Float64Sqrt(Node* a) { return AddNode(machine()->Float64Sqrt(), a); }