[UtilityClass] [issue #2384] Added a test to confirm no issue.

added some tests to confirm that lombok makes things static if needed.

test/transform/resource/after-ecj/UtilityClassInner.java

@@ -0,0 +1,11 @@
+class UtilityClassInner {
+  static final @lombok.experimental.UtilityClass class UtilClass {
+    private @java.lang.SuppressWarnings("all") UtilClass() {
+      super();
+      throw new java.lang.UnsupportedOperationException("This is a utility class and cannot be instantiated");
+    }
+  }
+  UtilityClassInner() {
+    super();
+  }
+}