fix unused import hints in src/generated/source.dart

pkg/analyzer/lib/src/generated/source.dart

Index: pkg/analyzer/lib/src/generated/source.dart
diff --git a/pkg/analyzer/lib/src/generated/source.dart b/pkg/analyzer/lib/src/generated/source.dart
index 169bf81b1b52e150a63b78a2b01af531d98fe70e..c9d1b45617c0f3a38b95af180dc1a99b1c904f53 100644
--- a/pkg/analyzer/lib/src/generated/source.dart
+++ b/pkg/analyzer/lib/src/generated/source.dart
@@ -8,8 +8,6 @@ import 'dart:collection';
 import "dart:math" as math;
 
 import 'package:analyzer/file_system/file_system.dart';
-import 'package:analyzer/file_system/physical_file_system.dart';
-import 'package:analyzer/source/package_map_resolver.dart';
 import 'package:analyzer/src/context/source.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/java_core.dart';
@@ -17,7 +15,6 @@ import 'package:analyzer/src/generated/java_engine.dart';
 import 'package:analyzer/src/generated/java_io.dart' show JavaFile;
 import 'package:analyzer/src/generated/sdk.dart' show DartSdk;
 import 'package:analyzer/src/generated/source_io.dart' show FileBasedSource;
-import 'package:analyzer/src/generated/utilities_dart.dart' as utils;
 import 'package:analyzer/task/model.dart';
 import 'package:package_config/packages.dart';
 import 'package:path/path.dart' as pathos;