Fix testAtMostOnceWithFailure test case

Author: RocMarshal

flink-connector-jdbc/src/test/java/org/apache/flink/connector/jdbc/source/JdbcSourceStreamRelatedITCase.java

@@ -197,7 +197,7 @@ void testAtMostOnceWithFailure(@InjectClusterClient ClusterClient<?> client) thr
                 env,
                 () ->
                         Math.abs(collectedRecords.size() - testEntries.size())
-                                <= DATA_NUM_PER_SECOND_SPAN_SPLIT);
+                                <= DATA_NUM_PER_SECOND_SPAN_SPLIT * TESTING_PARALLELISM);
 
         assertThat(testEntries)
                 .hasSizeGreaterThanOrEqualTo(collectedRecords.size())