dart2js: run dartfmt on tests

tests/compiler/dart2js_extra/consistent_null_add_error_test.dart

Index: tests/compiler/dart2js_extra/consistent_null_add_error_test.dart
diff --git a/tests/compiler/dart2js_extra/consistent_null_add_error_test.dart b/tests/compiler/dart2js_extra/consistent_null_add_error_test.dart
index 2c47018903f061c7d85f13b38c65e374a80a50a1..8284ff9846a707817f5a89ebfe66be021801db70 100644
--- a/tests/compiler/dart2js_extra/consistent_null_add_error_test.dart
+++ b/tests/compiler/dart2js_extra/consistent_null_add_error_test.dart
@@ -8,7 +8,6 @@ import "package:expect/expect.dart";
 //
 // They don't, sometimes we generate null.$add, sometimes JSNull_methods.$add.
 
-
 @NoInline()
 @AssumeDynamic()
 confuse(x) => x;
@@ -37,7 +36,6 @@ void check(String name, f1, f2, [f3, f4, f5, f6]) {
   if (f6 != null) check2(name, 'f1', f1, 'f6', f6);
 }
 
-
 class NullPlusInt {
   static f1() {
     return confuse(null) + confuse(1);