Reorganize some pub libraries.

sdk/lib/_internal/pub/test/test_pub.dart

Index: sdk/lib/_internal/pub/test/test_pub.dart
diff --git a/sdk/lib/_internal/pub/test/test_pub.dart b/sdk/lib/_internal/pub/test/test_pub.dart
index c35ab69efa0e0075817813ff9dac81433dffd156..b3bbc8257dc26bc3a7571dc9ecd52c6017997f91 100644
--- a/sdk/lib/_internal/pub/test/test_pub.dart
+++ b/sdk/lib/_internal/pub/test/test_pub.dart
@@ -28,13 +28,13 @@ import '../lib/src/entrypoint.dart';
 // with the git descriptor method. Maybe we should try to clean up the top level
 // scope a bit?
 import '../lib/src/git.dart' as gitlib;
-import '../lib/src/git_source.dart';
-import '../lib/src/hosted_source.dart';
 import '../lib/src/http.dart';
 import '../lib/src/io.dart';
 import '../lib/src/log.dart' as log;
-import '../lib/src/path_source.dart';
 import '../lib/src/safe_http_server.dart';
+import '../lib/src/source/git.dart';
+import '../lib/src/source/hosted.dart';
+import '../lib/src/source/path.dart';
 import '../lib/src/system_cache.dart';
 import '../lib/src/utils.dart';
 import '../lib/src/validator.dart';