[FLINK-20536][tests] Update migration tests of ContinuousFileProcessingMigrationTest to cover migration from 1.12

Author: dianfu

flink-fs-tests/src/test/java/org/apache/flink/hdfstests/ContinuousFileProcessingMigrationTest.java

@@ -81,7 +81,8 @@ public static Collection<Tuple2<MigrationVersion, Long>> parameters() {
                 Tuple2.of(MigrationVersion.v1_8, 1555215710000L),
                 Tuple2.of(MigrationVersion.v1_9, 1567499868000L),
                 Tuple2.of(MigrationVersion.v1_10, 1594559333000L),
-                Tuple2.of(MigrationVersion.v1_11, 1594561663000L));
+                Tuple2.of(MigrationVersion.v1_11, 1594561663000L),
+                Tuple2.of(MigrationVersion.v1_12, 1613720148000L));
     }
 
     /**