[HUDI-1989] Fix flakiness in TestHoodieMergeOnReadTable (#3574)

* [HUDI-1989] Refactor clustering tests for MoR table

* refactor assertion helper

* add CheckedFunction

* SparkClientFunctionalTestHarness.java

* put back original test case

* move testcases out from TestHoodieMergeOnReadTable.java

* add TestHoodieSparkMergeOnReadTableRollback.java

* use SparkClientFunctionalTestHarness

* add tag

hudi-common/src/test/java/org/apache/hudi/common/testutils/CheckedFunction.java

@@ -0,0 +1,25 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ */
+
+package org.apache.hudi.common.testutils;
+
+@FunctionalInterface
+public interface CheckedFunction<T, R> {
+  R apply(T t) throws Exception;
+}