Remove uses of unittest in the HTML tests where possible.

pkg/dev_compiler/test/codegen/lib/html/range_test.dart

Index: pkg/dev_compiler/test/codegen/lib/html/range_test.dart
diff --git a/pkg/dev_compiler/test/codegen/lib/html/range_test.dart b/pkg/dev_compiler/test/codegen/lib/html/range_test.dart
index 5c2028d051f2d8af57f23c24b617b6e5508fc8b9..01739fd1c5a84e6926d8894d6b4f953ab868f342 100644
--- a/pkg/dev_compiler/test/codegen/lib/html/range_test.dart
+++ b/pkg/dev_compiler/test/codegen/lib/html/range_test.dart
@@ -1,12 +1,8 @@
-library range_test;
-
 import 'dart:html';
-import 'package:unittest/unittest.dart';
-import 'package:unittest/html_individual_config.dart';
 
-main() {
-  useHtmlIndividualConfiguration();
+import 'package:expect/minitest.dart';
 
+main() {
   group('supported', () {
     test('supports_createContextualFragment', () {
       expect(Range.supportsCreateContextualFragment, isTrue);