Fix missing edge in member pool collection

Bug: 65810338
Change-Id: Ic0e196345645f77e5c651d33137d4ac6b3923e48
diff --git a/src/main/java/com/android/tools/r8/ir/optimize/MethodPoolCollection.java b/src/main/java/com/android/tools/r8/ir/optimize/MethodPoolCollection.java
index 49b4782..5edad12 100644
--- a/src/main/java/com/android/tools/r8/ir/optimize/MethodPoolCollection.java
+++ b/src/main/java/com/android/tools/r8/ir/optimize/MethodPoolCollection.java
@@ -55,6 +55,7 @@
           if (subClazz != null) {
             MemberPool<DexMethod> childPool =
                 memberPools.computeIfAbsent(subClazz, k -> new MemberPool<>(equivalence));
+            methodPool.linkSubtype(childPool);
             childPool.linkInterface(methodPool);
           }
         }