Cache PackageBundle instances in AnalyzerWorkerLoop and reuse for multiple requests.

pkg/analyzer_cli/test/build_mode_test.dart

Index: pkg/analyzer_cli/test/build_mode_test.dart
diff --git a/pkg/analyzer_cli/test/build_mode_test.dart b/pkg/analyzer_cli/test/build_mode_test.dart
index 6ccff0d657d0152258aa7570ebd3f24c3f8ef0cd..0756f1ff52b8d58ac2d6e2df327850e552b30525 100644
--- a/pkg/analyzer_cli/test/build_mode_test.dart
+++ b/pkg/analyzer_cli/test/build_mode_test.dart
@@ -32,7 +32,7 @@ class TestAnalyzerWorkerLoop extends AnalyzerWorkerLoop {
       : super(new MemoryResourceProvider(), connection);
 
   @override
-  Future<Null> analyze(CommandLineOptions options) async {
+  Future<Null> analyze(CommandLineOptions options, inputs) async {
     if (_analyze != null) {
       _analyze(options);
     }