Extend extension registry shrinking to extensions that do not inherit from GeneratedMessageLite

Change-Id: I44e0d0ea29c3ac02817dc4e6622152f1e72e78e1
diff --git a/src/main/java/com/android/tools/r8/ir/analysis/proto/GeneratedExtensionRegistryShrinker.java b/src/main/java/com/android/tools/r8/ir/analysis/proto/GeneratedExtensionRegistryShrinker.java
index c39cea7..7696a8b 100644
--- a/src/main/java/com/android/tools/r8/ir/analysis/proto/GeneratedExtensionRegistryShrinker.java
+++ b/src/main/java/com/android/tools/r8/ir/analysis/proto/GeneratedExtensionRegistryShrinker.java
@@ -205,10 +205,6 @@
       return false;
     }
 
-    if (!appView.isSubtype(clazz.type, references.generatedMessageLiteType).isTrue()) {
-      return false;
-    }
-
     FieldAccessInfo fieldAccessInfo = fieldAccessInfoCollection.get(encodedField.field);
     if (fieldAccessInfo == null) {
       return false;