Fix dangling SingleImplementations left after class unloading

Test: make test-art-host, manual using sample code

bug: 73143991

Change-Id: I4d56b39c69d4ed60266a8b90b9e9d18fba7b8227
diff --git a/test/616-cha-unloading/src/AbstractCHATester.java b/test/616-cha-unloading/src/AbstractCHATester.java
new file mode 100644
index 0000000..e110945
--- /dev/null
+++ b/test/616-cha-unloading/src/AbstractCHATester.java
@@ -0,0 +1,19 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+public abstract class AbstractCHATester {
+  public abstract void lonelyMethod();
+}