Reland 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..ed4147fd2760cd16265ec4ebd8e6776188db5c9f 100644
--- a/tests/language/vm/causal_async_exception_stack_test.dart
+++ b/tests/language/vm/causal_async_exception_stack_test.dart
@@ -1,4 +1,4 @@
-// Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
+// Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
@@ -24,18 +24,52 @@ foo() async {
 }
 
 main() async {
+  // Test async and async*.
   try {
     await foo();
   } catch (e, st) {
     expect(st.toString(), stringContainsInOrder([
-        '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',
         ]));
   }
+
+  inner() async {
+    deep() async {
+      await thrower();
+    }
+    await deep();
+  }
+
+  // Test inner functions.
+  try {
+    await inner();
+  } catch (e, st) {
+    expect(st.toString(), stringContainsInOrder([
+          'thrower',
+          '<asynchronous suspension>',
+          'main.inner.deep',
+          '<asynchronous suspension>',
+          'main.inner',
+          '<asynchronous suspension>',
+          'main',
+          '<asynchronous suspension>',
+          ]));
+  }
+
+  // Test for correct linkage.
+  try {
+    await thrower();
+  } catch(e, st) {
+    expect(st.toString(), stringContainsInOrder([
+           'thrower',
+           '<asynchronous suspension>',
+           'main',
+           ]));
+  }
 }