Use trackCacheDependencies for performance speedup

lib/src/analyzer/context.dart

Index: lib/src/analyzer/context.dart
diff --git a/lib/src/analyzer/context.dart b/lib/src/analyzer/context.dart
index 2bb9f7b2abce953c161c76f093371bc53e11ecd8..1ba395314944eda30df6f3f25e8311785b3d67fe 100644
--- a/lib/src/analyzer/context.dart
+++ b/lib/src/analyzer/context.dart
@@ -142,7 +142,9 @@ AnalysisContext createAnalysisContextWithSources(AnalyzerOptions options,
 /// Creates an analysis context that contains our restricted typing rules.
 AnalysisContextImpl createAnalysisContext() {
   var res = AnalysisEngine.instance.createAnalysisContext();
-  res.analysisOptions = new AnalysisOptionsImpl()..strongMode = true;
+  res.analysisOptions = new AnalysisOptionsImpl()
+    ..strongMode = true
+    ..trackCacheDependencies = false;
   return res;
 }