NullPointerException in SeqTsFileRecoverTest.java and UnseqTsFileRecoverTest

see

https://builds.apache.org/job/IoTDB-Pipeline/job/master/154/

Stacktrace

java.lang.NullPointerException at org.apache.iotdb.db.writelog.recover.UnseqTsFileRecoverTest.test(UnseqTsFileRecoverTest.java:130)

Standard Output

INFO [2019-08-12 23:42:02,269] [main] org.apache.iotdb.db.writelog.node.ExclusiveWriteLogNode:74 - create the WAL folder {}.data/wal/testNodetest.ts INFO [2019-08-12 23:42:02,605] [main] org.apache.iotdb.tsfile.read.TsFileSequenceReader:608 - TsFile self-check cannot proceed at position 20952 after 10 chunk groups recovered, because : reach the end of the file.