[api] add API for Promise status and result.

src/code-stub-assembler.cc

Index: src/code-stub-assembler.cc
diff --git a/src/code-stub-assembler.cc b/src/code-stub-assembler.cc
index 06f8b8d8f4ab69e67cd2e459270d50dea0116360..515a1483e6df7f5039eee97d7e742272b0839d86 100644
--- a/src/code-stub-assembler.cc
+++ b/src/code-stub-assembler.cc
@@ -8340,7 +8340,7 @@ Node* CodeStubAssembler::AllocateJSPromise(Node* context) {
 
 void CodeStubAssembler::PromiseInit(Node* promise) {
   StoreObjectField(promise, JSPromise::kStatusOffset,
-                   SmiConstant(kPromisePending));
+                   SmiConstant(v8::Promise::kPending));
   StoreObjectField(promise, JSPromise::kFlagsOffset, SmiConstant(0));
 }