[turbofan] Introduce Float64Pow and NumberPow operators.

src/compiler/machine-operator-reducer.h

Index: src/compiler/machine-operator-reducer.h
diff --git a/src/compiler/machine-operator-reducer.h b/src/compiler/machine-operator-reducer.h
index e44521ec7870c5faf6369cf401da13b57e262893..e25e3b67c491e2764d503e286b5eb81f6fc1871a 100644
--- a/src/compiler/machine-operator-reducer.h
+++ b/src/compiler/machine-operator-reducer.h
@@ -34,6 +34,8 @@ class MachineOperatorReducer final : public Reducer {
   Node* Uint32Constant(uint32_t value) {
     return Int32Constant(bit_cast<uint32_t>(value));
   }
+  Node* Float64Mul(Node* lhs, Node* rhs);
+  Node* Float64PowHalf(Node* value);
   Node* Word32And(Node* lhs, Node* rhs);
   Node* Word32And(Node* lhs, uint32_t rhs) {
     return Word32And(lhs, Uint32Constant(rhs));