Add missing classes to MergedTypeBaseTest

This CL fixes a bad merge from https://r8-review.googlesource.com/c/r8/+/28622.

Change-Id: I4f3acbffce293912e901e1d020b31296ebc8614c
diff --git a/src/test/java/com/android/tools/r8/shaking/ifrule/verticalclassmerging/MergedTypeBaseTest.java b/src/test/java/com/android/tools/r8/shaking/ifrule/verticalclassmerging/MergedTypeBaseTest.java
index 2b9fec7..cda8096 100644
--- a/src/test/java/com/android/tools/r8/shaking/ifrule/verticalclassmerging/MergedTypeBaseTest.java
+++ b/src/test/java/com/android/tools/r8/shaking/ifrule/verticalclassmerging/MergedTypeBaseTest.java
@@ -55,7 +55,7 @@
     this.enableVerticalClassMerging = enableVerticalClassMerging;
     this.classes =
         ImmutableList.<Class>builder()
-            .add(A.class, B.class, C.class, Unused.class, getTestClass())
+            .add(A.class, B.class, C.class, I.class, J.class, K.class, Unused.class, getTestClass())
             .addAll(additionalClasses)
             .build();
   }