Flush results when contexts are made idle.

pkg/analyzer/test/generated/engine_test.dart

Index: pkg/analyzer/test/generated/engine_test.dart
diff --git a/pkg/analyzer/test/generated/engine_test.dart b/pkg/analyzer/test/generated/engine_test.dart
index a21b8961b28a64441d9c53403ffcaf8cd2e05897..1e3ec09f437eb8a9011c9bff334be36715124916 100644
--- a/pkg/analyzer/test/generated/engine_test.dart
+++ b/pkg/analyzer/test/generated/engine_test.dart
@@ -277,6 +277,15 @@ class TestAnalysisContext implements InternalAnalysisContext {
     return null;
   }
 
+  bool get isActive {
+    fail("Unexpected invocation of isActive");
+    return false;
+  }
+
+  void set isActive(bool isActive) {
+    fail("Unexpected invocation of isActive");
+  }
+
   @override
   bool get isDisposed {
     fail("Unexpected invocation of isDisposed");