Run dartfmt on all files under runtime.

runtime/observatory/tests/service/async_scope_test.dart

Index: runtime/observatory/tests/service/async_scope_test.dart
diff --git a/runtime/observatory/tests/service/async_scope_test.dart b/runtime/observatory/tests/service/async_scope_test.dart
index 170a638b7c26709c81ee884a54bf3b025947599c..d7525dd5801f676c89e6eb1a9fda01f00b4eb2bd 100644
--- a/runtime/observatory/tests/service/async_scope_test.dart
+++ b/runtime/observatory/tests/service/async_scope_test.dart
@@ -34,7 +34,6 @@ testeeDo() {
   });
 }
 
-
 checkAsyncVarDescriptors(Isolate isolate) async {
   ServiceMap stack = await isolate.getStack();
   expect(stack.type, equals('Stack'));
@@ -44,7 +43,6 @@ checkAsyncVarDescriptors(Isolate isolate) async {
   expect(vars, equals('param1 local1')); // no :async_op et al
 }
 
-
 checkAsyncStarVarDescriptors(Isolate isolate) async {
   ServiceMap stack = await isolate.getStack();
   expect(stack.type, equals('Stack'));
@@ -54,7 +52,6 @@ checkAsyncStarVarDescriptors(Isolate isolate) async {
   expect(vars, equals('param2 local2')); // no :async_op et al
 }
 
-
 var tests = [
   hasStoppedAtBreakpoint, // debugger()
   setBreakpointAtLine(LINE_A),