Desugar async/await to create the resulting Promise upfront

src/parsing/parser.h

Index: src/parsing/parser.h
diff --git a/src/parsing/parser.h b/src/parsing/parser.h
index 1648700d2aaa931a3b4f6e00c44dc8bf63db3e09..b3ca25d36ececd0cf33ef35fb0d43e663bc7ec66 100644
--- a/src/parsing/parser.h
+++ b/src/parsing/parser.h
@@ -1122,7 +1122,7 @@ class Parser : public ParserBase<ParserTraits> {
 
   Block* BuildParameterInitializationBlock(
       const ParserFormalParameters& parameters, bool* ok);
-  Block* BuildRejectPromiseOnException(Block* block);
+  Block* BuildRejectPromiseOnException(Block* block, bool* ok);
 
   // Consumes the ending }.
   ZoneList<Statement*>* ParseEagerFunctionBody(
@@ -1168,8 +1168,10 @@ class Parser : public ParserBase<ParserTraits> {
   void RewriteParameterInitializer(Expression* expr, Scope* scope);
 
   Expression* BuildCreateJSGeneratorObject(int pos, FunctionKind kind);
-  Expression* BuildPromiseResolve(Expression* value, int pos);
-  Expression* BuildPromiseReject(Expression* value, int pos);
+  Expression* BuildResolvePromise(Expression* value, int pos);
+  Expression* BuildRejectPromise(Expression* value, int pos);
+  VariableProxy* BuildDotPromise();
+  VariableProxy* BuildDebugIsActive();
 
   Scanner scanner_;
   PreParser* reusable_preparser_;
@@ -1358,7 +1360,8 @@ void ParserTraits::AddParameterInitializationBlock(
     if (!*ok) return;
 
     if (is_async) {
-      init_block = parser_->BuildRejectPromiseOnException(init_block);
+      init_block = parser_->BuildRejectPromiseOnException(init_block, ok);
+      if (!*ok) return;
     }
 
     if (init_block != nullptr) {