[promises] Refactor CreatePromise

src/code-stub-assembler.h

Index: src/code-stub-assembler.h
diff --git a/src/code-stub-assembler.h b/src/code-stub-assembler.h
index bf0fb1f0606c424cdbe727b74a6a0b019239636c..836aab7b78573988efadc643edbf1284f69b9ba8 100644
--- a/src/code-stub-assembler.h
+++ b/src/code-stub-assembler.h
@@ -1053,6 +1053,13 @@ class V8_EXPORT_PRIVATE CodeStubAssembler : public compiler::CodeAssembler {
   // Promise helpers
   Node* IsPromiseHookEnabled();
 
+  Node* AllocateJSPromise(Node* context);
+  void PromiseInit(Node* promise);
+
+  // Other promise fields may also be need to set/reset. This only
+  // provides a helper for certain init patterns.
+  void PromiseSet(Node* promise, Node* status, Node* result);
+
  protected:
   void DescriptorLookupLinear(Node* unique_name, Node* descriptors, Node* nof,
                               Label* if_found, Variable* var_name_index,