Reduce log level of TsFileGenerator #29961

Job	Run time
unit-test (17, windows-latest, others)	28m 26s
unit-test (17, ubuntu-latest, others)	20m 11s
unit-test (17, windows-latest, datanode)	35m 2s
unit-test (17, ubuntu-latest, datanode)	23m 4s
	1h 46m 43s

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