Fix test to not depend on analyzer error message.

test/formatter_test.dart

Index: test/formatter_test.dart
diff --git a/test/formatter_test.dart b/test/formatter_test.dart
index b50271f0683d70707950008a2acee6f16392aa8f..4e3df04454ee9077f91b870dbc311559719fce9c 100644
--- a/test/formatter_test.dart
+++ b/test/formatter_test.dart
@@ -81,11 +81,9 @@ void main() {
       new DartFormatter().formatStatement("var x = 1;;");
 
       fail("Should throw.");
-    } catch (err) {
-      expect(err, new isInstanceOf<FormatterException>());
-      var message = err.message();
-      expect(message, contains("Unexpected token"));
-      expect(message, contains("column 11"));
+    } on FormatterException catch (ex) {
+      expect(ex.errors.length, equals(1));
+      expect(ex.errors.first.offset, equals(10));
     }
   });