Move pub into sdk/lib/_internal.

sdk/lib/_internal/pub/test/validator/lib_test.dart

Index: sdk/lib/_internal/pub/test/validator/lib_test.dart
diff --git a/utils/tests/pub/validator/lib_test.dart b/sdk/lib/_internal/pub/test/validator/lib_test.dart
similarity index 91%
rename from utils/tests/pub/validator/lib_test.dart
rename to sdk/lib/_internal/pub/test/validator/lib_test.dart
index 6f9a38a29ff28b965757c176fcb4c43f3ea4bb8d..13f13f14896e4686771c6b4b7a09cea196c24219 100644
--- a/utils/tests/pub/validator/lib_test.dart
+++ b/sdk/lib/_internal/pub/test/validator/lib_test.dart
@@ -5,10 +5,10 @@
 import 'package:pathos/path.dart' as path;
 import 'package:scheduled_test/scheduled_test.dart';
 
-import '../../../pub/entrypoint.dart';
-import '../../../pub/io.dart';
-import '../../../pub/validator.dart';
-import '../../../pub/validator/lib.dart';
+import 'package:pub/src/entrypoint.dart';
+import 'package:pub/src/io.dart';
+import 'package:pub/src/validator.dart';
+import 'package:pub/src/validator/lib.dart';
 import '../descriptor.dart' as d;
 import '../test_pub.dart';
 import 'utils.dart';