Remove invalidated elements from enqueuer and resolution.

pkg/compiler/lib/src/common/resolution.dart

Index: pkg/compiler/lib/src/common/resolution.dart
diff --git a/pkg/compiler/lib/src/common/resolution.dart b/pkg/compiler/lib/src/common/resolution.dart
index ce41703a851c4f15c96cd80ba2af0f2c9b596f2c..76031637ef2965b7df0a2068945b627983afe9b6 100644
--- a/pkg/compiler/lib/src/common/resolution.dart
+++ b/pkg/compiler/lib/src/common/resolution.dart
@@ -243,6 +243,8 @@ abstract class Resolution implements Frontend {
   /// Later calls to [getWorldImpact] or [computeWorldImpact] returns an empty
   /// impact.
   void emptyCache();
+
+  void forgetElement(Element element);
 }
 
 /// A container of commonly used dependencies for tasks that involve parsing.