Test: Fix utest fail for StUtimeInMicroseconds. v7.0.20 (#4218) #3646

Job	Run time
cygwin64-cache	1m 39s
multiple-arch-aarch64	22m 54s
utest-regression-blackbox-test	9m 25s
multiple-arch-armv7	22m 0s
fast	1s
cygwin64	15m 7s
build-ubuntu20	3m 31s
build-ubuntu16	3m 6s
build-cross-aarch64	5m 2s
build-centos7	5m 0s
build-cross-arm	5m 15s
build-ubuntu18	3m 10s
coverage	3m 33s
multiple-arch-amd64	2m 27s
test-done	1s
	1h 42m 11s

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