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 b069f9af980014a879e2cb18e424036ae7e05156..11310d61a567dff55f8e96712c1849e982d789d9 100644
--- a/src/parsing/parser.h
+++ b/src/parsing/parser.h
@@ -768,7 +768,7 @@ class Parser : public ParserBase<Parser> {
 
   Block* BuildParameterInitializationBlock(
       const ParserFormalParameters& parameters, bool* ok);
-  Block* BuildRejectPromiseOnException(Block* block);
+  Block* BuildRejectPromiseOnException(Block* block, bool* ok);
 
   // Consumes the ending }.
   ZoneList<Statement*>* ParseEagerFunctionBody(
@@ -862,8 +862,10 @@ class Parser : public ParserBase<Parser> {
   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();
 
   // Generic AST generator for throwing errors from compiled code.
   Expression* NewThrowError(Runtime::FunctionId function_id,
@@ -1000,7 +1002,8 @@ void ParserBaseTraits<Parser>::AddParameterInitializationBlock(
     if (!*ok) return;
 
     if (is_async) {
-      init_block = delegate()->BuildRejectPromiseOnException(init_block);
+      init_block = delegate()->BuildRejectPromiseOnException(init_block, ok);
+      if (!*ok) return;
     }
 
     if (init_block != nullptr) {