[async await] fix async await desugaring

src/parsing/parser.h

Index: src/parsing/parser.h
diff --git a/src/parsing/parser.h b/src/parsing/parser.h
index 20c79371822276d08a8b1691a4855a9fb090ad59..81c4255aafc053940d1391335735057c9a4bdd3c 100644
--- a/src/parsing/parser.h
+++ b/src/parsing/parser.h
@@ -543,6 +543,7 @@ class V8_EXPORT_PRIVATE Parser : public NON_EXPORTED_BASE(ParserBase<Parser>) {
   Block* BuildParameterInitializationBlock(
       const ParserFormalParameters& parameters, bool* ok);
   Block* BuildRejectPromiseOnException(Block* block);
+  Block* BuildRejectPromiseOnExceptionForParameters(Block* block);
 
   ZoneList<Statement*>* ParseFunction(
       const AstRawString* function_name, int pos, FunctionKind kind,
@@ -628,9 +629,10 @@ class V8_EXPORT_PRIVATE Parser : public NON_EXPORTED_BASE(ParserBase<Parser>) {
 
   Expression* BuildInitialYield(int pos, FunctionKind kind);
   Assignment* BuildCreateJSGeneratorObject(int pos, FunctionKind kind);
-  Expression* BuildResolvePromise(Expression* value, int pos);
-  Expression* BuildRejectPromise(Expression* value, int pos);
+  Expression* BuildResolvePromise();
+  Expression* BuildRejectPromise(Variable* value);
   Variable* PromiseVariable();
+  Variable* AsyncReturnVariable();
 
   // Generic AST generator for throwing errors from compiled code.
   Expression* NewThrowError(Runtime::FunctionId function_id,
@@ -1042,7 +1044,7 @@ class V8_EXPORT_PRIVATE Parser : public NON_EXPORTED_BASE(ParserBase<Parser>) {
     auto* init_block = BuildParameterInitializationBlock(parameters, ok);
     if (!*ok) return;
     if (is_async) {
-      init_block = BuildRejectPromiseOnException(init_block);
+      init_block = BuildRejectPromiseOnExceptionForParameters(init_block);
     }
     if (init_block != nullptr) body->Add(init_block, zone());
   }