Revert "Store actual Reference(s) for additional exports."

pkg/kernel/lib/import_table.dart

Index: pkg/kernel/lib/import_table.dart
diff --git a/pkg/kernel/lib/import_table.dart b/pkg/kernel/lib/import_table.dart
index c892e5ee5df7314ffba0a965867ca0d32ce85d48..89c2998256d7015891c7e6167ba8a756b0d14334 100644
--- a/pkg/kernel/lib/import_table.dart
+++ b/pkg/kernel/lib/import_table.dart
@@ -102,13 +102,6 @@ class _ImportTableBuilder extends RecursiveVisitor {
     addLibraryImport(node.enclosingLibrary);
   }
 
-  visitLibrary(Library node) {
-    super.visitLibrary(node);
-    for (Reference exportedReference in node.additionalExports) {
-      addLibraryImport(exportedReference.node.parent);
-    }
-  }
-
   defaultMemberReference(Member node) {
     addLibraryImport(node.enclosingLibrary);
   }