Improvements to causal async stack traces

tests/language/vm/causal_async_exception_stack_test.dart

Index: tests/language/vm/causal_async_exception_stack_test.dart
diff --git a/tests/language/vm/causal_async_exception_stack_test.dart b/tests/language/vm/causal_async_exception_stack_test.dart
index 5e8eee0061fb72b969dfb62e854af83bdae0f8a2..6bf2253d96b548bd50c1eaf7f9d1f903d0145fb1 100644
--- a/tests/language/vm/causal_async_exception_stack_test.dart
+++ b/tests/language/vm/causal_async_exception_stack_test.dart
@@ -28,14 +28,13 @@ main() async {
     await foo();
   } catch (e, st) {
     expect(st.toString(), stringContainsInOrder([

[rmacnak, 2017/02/10 21:27:14]

Since we're futzing with qualified names, add also a test that includes a local
function in the stack. Something like

main() {
  inner() async {
     await thrower();
  }
  inner();
}

should give

thrower
<gap>
main.inner
<gap>
main

[Cutch, 2017/02/11 00:02:40]

Done.

-        'thrower.<thrower_async_body>',
-        '<asynchronous suspension>',
         'thrower',
-        'generator.<generator_async_gen_body>',
         '<asynchronous suspension>',
         'generator',
-        'foo.<foo_async_body>',
         '<asynchronous suspension>',
+        'foo',
+        '<asynchronous suspension>',
+        'main',
         ]));
   }
 }