Format all tests.

tests/language/string_interpolation_and_buffer_test.dart

Index: tests/language/string_interpolation_and_buffer_test.dart
diff --git a/tests/language/string_interpolation_and_buffer_test.dart b/tests/language/string_interpolation_and_buffer_test.dart
index 45690277357e1e6e1138d05e60b4fd386aa942ad..7f72246747b581c2a7b14782b1ee692e0366af82 100644
--- a/tests/language/string_interpolation_and_buffer_test.dart
+++ b/tests/language/string_interpolation_and_buffer_test.dart
@@ -37,7 +37,7 @@ main() {
       } on TypeError {
         return 'Error';
       } on ArgumentError {
-        return 'Error';  // Checked mode.
+        return 'Error'; // Checked mode.
       }
     } else {
       try {
@@ -58,7 +58,7 @@ main() {
       } on TypeError {
         return 'Error';
       } on ArgumentError {
-        return 'Error';  // Checked mode.
+        return 'Error'; // Checked mode.
       }
     } else {
       try {
@@ -79,7 +79,7 @@ main() {
       } on TypeError {
         return 'Error';
       } on ArgumentError {
-        return 'Error';  // Checked mode.
+        return 'Error'; // Checked mode.
       }
     } else {
       try {