Add a flag for caching all analysis results in the driver.

pkg/analyzer/test/src/dart/analysis/base.dart

Index: pkg/analyzer/test/src/dart/analysis/base.dart
diff --git a/pkg/analyzer/test/src/dart/analysis/base.dart b/pkg/analyzer/test/src/dart/analysis/base.dart
index 601c2fe2b54cb9bc16c913c159a8f8dc0f5fe190..6270250b13c02c6bae2b0045fc21ab67e2059b9c 100644
--- a/pkg/analyzer/test/src/dart/analysis/base.dart
+++ b/pkg/analyzer/test/src/dart/analysis/base.dart
@@ -63,6 +63,8 @@ class BaseAnalysisDriverTest {
   String testFile;
   String testCode;
 
+  bool get disableChangesAndCacheAllResults => false;
+
   void addTestFile(String content, {bool priority: false}) {
     testCode = content;
     provider.newFile(testFile, content);
@@ -124,7 +126,8 @@ class BaseAnalysisDriverTest {
         ], null, provider),
         new AnalysisOptionsImpl()
           ..strongMode = true
-          ..enableUriInPartOf = true);
+          ..enableUriInPartOf = true,
+        disableChangesAndCacheAllResults: disableChangesAndCacheAllResults);
     scheduler.start();
     scheduler.status.listen(allStatuses.add);
     driver.results.listen(allResults.add);