Move byte_store.dart and file_byte_store.dart to their own subdirectory.

pkg/analyzer/test/src/summary/resynthesize_kernel_test.dart

Index: pkg/analyzer/test/src/summary/resynthesize_kernel_test.dart
diff --git a/pkg/analyzer/test/src/summary/resynthesize_kernel_test.dart b/pkg/analyzer/test/src/summary/resynthesize_kernel_test.dart
index e7ec0cebf272f569fade9b4ae35a4c0369293461..cc085ff2355abe9252bb507a1e768a3038245ae7 100644
--- a/pkg/analyzer/test/src/summary/resynthesize_kernel_test.dart
+++ b/pkg/analyzer/test/src/summary/resynthesize_kernel_test.dart
@@ -18,7 +18,7 @@ import 'package:front_end/src/base/performace_logger.dart';
 import 'package:front_end/src/base/libraries_specification.dart';
 import 'package:front_end/src/base/processed_options.dart';
 import 'package:front_end/src/fasta/uri_translator_impl.dart';
-import 'package:front_end/src/incremental/byte_store.dart';
+import 'package:front_end/src/byte_store/byte_store.dart';
 import 'package:front_end/src/incremental/kernel_driver.dart';
 import 'package:kernel/kernel.dart' as kernel;
 import 'package:kernel/target/targets.dart';