Add an analysis option to disable cache flushing.

pkg/analyzer/lib/src/context/context.dart

Index: pkg/analyzer/lib/src/context/context.dart
diff --git a/pkg/analyzer/lib/src/context/context.dart b/pkg/analyzer/lib/src/context/context.dart
index f56c12cc3c1a86f86c224ff8933c59517ea8461f..48a2da24697f91e69fb200a5f65c919837ee85ea 100644
--- a/pkg/analyzer/lib/src/context/context.dart
+++ b/pkg/analyzer/lib/src/context/context.dart
@@ -334,6 +334,7 @@ class AnalysisContextImpl implements InternalAnalysisContext {
     }
     this._options.strongMode = options.strongMode;
     this._options.trackCacheDependencies = options.trackCacheDependencies;
+    this._options.disableCacheFlushing = options.disableCacheFlushing;
     this._options.finerGrainedInvalidation = options.finerGrainedInvalidation;
     if (options is AnalysisOptionsImpl) {
       this._options.strongModeHints = options.strongModeHints;