Blacklist PackageFactory$BuiltInRuleFunction from serialization.

PiperOrigin-RevId: 206389059
diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/serialization/AutoRegistry.java b/src/main/java/com/google/devtools/build/lib/skyframe/serialization/AutoRegistry.java
index f84611e..fb3660e 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/serialization/AutoRegistry.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/serialization/AutoRegistry.java
@@ -42,7 +42,8 @@
   private static final ImmutableList<String> CLASS_NAME_PREFIX_BLACKLIST =
       ImmutableList.of(
           "com.google.devtools.build.lib.vfs",
-          "com.google.devtools.build.lib.actions.ArtifactFactory");
+          "com.google.devtools.build.lib.actions.ArtifactFactory",
+          "com.google.devtools.build.lib.packages.PackageFactory$BuiltInRuleFunction");
 
   /** Classes outside {@link AutoRegistry#PACKAGE_PREFIX} that need to be serialized. */
   private static final ImmutableList<String> EXTERNAL_CLASS_NAMES_TO_REGISTER =