Run dartfmt on all files under runtime.

runtime/observatory/tests/service/causal_async_stack_contents_test.dart

Index: runtime/observatory/tests/service/causal_async_stack_contents_test.dart
diff --git a/runtime/observatory/tests/service/causal_async_stack_contents_test.dart b/runtime/observatory/tests/service/causal_async_stack_contents_test.dart
index cfdc667aa9d354a17a576bfc6b4479c3cef040af..99b10b2b1ae5fee0331a8d2db619777a211f6713 100644
--- a/runtime/observatory/tests/service/causal_async_stack_contents_test.dart
+++ b/runtime/observatory/tests/service/causal_async_stack_contents_test.dart
@@ -16,18 +16,18 @@ const LINE_B = 30;
 
 foobar() {
   debugger();
-  print('foobar');  // LINE_C.
+  print('foobar'); // LINE_C.
 }
 
 helper() async {
   debugger();
-  print('helper');  // LINE_A.
+  print('helper'); // LINE_A.
   foobar();
 }
 
 testMain() {
   debugger();
-  helper();  // LINE_B.
+  helper(); // LINE_B.
 }
 
 var tests = [
@@ -41,7 +41,6 @@ var tests = [
   resumeIsolate,
   hasStoppedAtBreakpoint,
   stoppedAtLine(LINE_A),
-
   (Isolate isolate) async {
     ServiceMap stack = await isolate.getStack();
     // Has causal frames (we are inside an async function)
@@ -51,11 +50,9 @@ var tests = [
     expect(asyncStack[1].kind, equals(M.FrameKind.asyncSuspensionMarker));
     expect(asyncStack[2].toString(), contains('testMain'));
   },
-
   resumeIsolate,
   hasStoppedAtBreakpoint,
   stoppedAtLine(LINE_C),
-
   (Isolate isolate) async {
     ServiceMap stack = await isolate.getStack();
     // Has causal frames (we are inside a function called by an async function)
@@ -74,6 +71,5 @@ var tests = [
   },
 ];
 
-main(args) => runIsolateTestsSynchronous(args,
-                                         tests,
-                                         testeeConcurrent: testMain);
+main(args) =>
+    runIsolateTestsSynchronous(args, tests, testeeConcurrent: testMain);