Fix parsing of awaitable expressions with nested functions

runtime/vm/parser.h

Index: runtime/vm/parser.h
===================================================================
--- runtime/vm/parser.h	(revision 41931)
+++ runtime/vm/parser.h	(working copy)
@@ -27,6 +27,7 @@
 class LocalVariable;
 class SourceLabel;
 template <typename T> class GrowableArray;
+class Parser;
 
 struct CatchParamDesc;
 class ClassDesc;
@@ -131,10 +132,7 @@
 
   void AllocateVariables();
 
-  void record_await() {
-    have_seen_await_expr_ = true;
-  }
-  void reset_have_seen_await() { have_seen_await_expr_ = false; }
+  void record_await() { have_seen_await_expr_ = true; }
   bool have_seen_await() const { return have_seen_await_expr_; }
 
   void set_saved_try_ctx(LocalVariable* saved_try_ctx) {
@@ -178,6 +176,7 @@
 
   Isolate* isolate_;
 
+  friend class Parser;
   DISALLOW_COPY_AND_ASSIGN(ParsedFunction);
 };