[turbofan] Introduce Float64Pow and NumberPow operators.

src/code-stubs.h

Index: src/code-stubs.h
diff --git a/src/code-stubs.h b/src/code-stubs.h
index 85b0883db849033869eae4c5df248d9f907d7c83..6090d505ebab0894fb4b5973d5d0762d06388054 100644
--- a/src/code-stubs.h
+++ b/src/code-stubs.h
@@ -1326,7 +1326,7 @@ class InternalArrayConstructorStub: public PlatformCodeStub {
 
 class MathPowStub: public PlatformCodeStub {
  public:
-  enum ExponentType { INTEGER, DOUBLE, TAGGED, ON_STACK };
+  enum ExponentType { INTEGER, DOUBLE, TAGGED };
 
   MathPowStub(Isolate* isolate, ExponentType exponent_type)
       : PlatformCodeStub(isolate) {
@@ -1334,9 +1334,7 @@ class MathPowStub: public PlatformCodeStub {
   }
 
   CallInterfaceDescriptor GetCallInterfaceDescriptor() const override {
-    if (exponent_type() == ON_STACK) {
-      return OnStackArgsDescriptorBase::ForArgs(isolate(), 2);
-    } else if (exponent_type() == TAGGED) {
+    if (exponent_type() == TAGGED) {
       return MathPowTaggedDescriptor(isolate());
     } else if (exponent_type() == INTEGER) {
       return MathPowIntegerDescriptor(isolate());