[tests] Update expected error NoSuchMethodError --> Error

Most (all?) implementations now throw ArgumentError since the
StreamIterator constructor no longer accepts null but the actual
type is not specified.
https://dart-review.googlesource.com/c/sdk/+/98001.

Change-Id: I10a24a67aa7353552c56d435ef206a2bc4f842fa
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/100987
Commit-Queue: Nicholas Shahan <nshahan@google.com>
Reviewed-by: Bob Nystrom <rnystrom@google.com>
diff --git a/tests/language_2/control_flow_collections/await_for_null_test.dart b/tests/language_2/control_flow_collections/await_for_null_test.dart
index 7e2fc5e..b2ba223 100644
--- a/tests/language_2/control_flow_collections/await_for_null_test.dart
+++ b/tests/language_2/control_flow_collections/await_for_null_test.dart
@@ -11,11 +11,11 @@
   asyncTest(() async {
     // Null stream.
     Stream<int> nullStream = null;
-    asyncExpectThrows<NoSuchMethodError>(
+    asyncExpectThrows<Error>(
         () async => <int>[await for (var i in nullStream) 1]);
-    asyncExpectThrows<NoSuchMethodError>(
+    asyncExpectThrows<Error>(
         () async => <int, int>{await for (var i in nullStream) 1: 1});
-    asyncExpectThrows<NoSuchMethodError>(
+    asyncExpectThrows<Error>(
         () async => <int>{await for (var i in nullStream) 1});
   });
 }