[debugger] omit exception events for rethrown exceptions in async.

src/parsing/parser-base.h

Index: src/parsing/parser-base.h
diff --git a/src/parsing/parser-base.h b/src/parsing/parser-base.h
index a946cfa6bc825bbca6162cdaf4d97105f6c9aa4c..71b703b0cabe6747010036431421840e72da00c9 100644
--- a/src/parsing/parser-base.h
+++ b/src/parsing/parser-base.h
@@ -2473,8 +2473,8 @@ ParserBase<Traits>::ParseYieldExpression(bool accept_IN,
   expression = Traits::BuildIteratorResult(expression, false);
   // Hackily disambiguate o from o.next and o [Symbol.iterator]().
   // TODO(verwaest): Come up with a better solution.
-  typename Traits::Type::YieldExpression yield =
-      factory()->NewYield(generator_object, expression, pos);
+  typename Traits::Type::YieldExpression yield = factory()->NewYield(
+      generator_object, expression, pos, Yield::kOnExceptionThrow);
   return yield;
 }