[SPARK-3868][PySpark] Hard to recognize which module is tested from unit-tests.log

./python/run-tests script display messages about which test it is running currently on stdout but not write them on unit-tests.log.
It is harder for us to recognize what test programs were executed and which test was failed.

Author: cocoatomo <cocoatomo77@gmail.com>

Closes #2724 from cocoatomo/issues/3868-display-testing-module-name and squashes the following commits:

c63d9fa [cocoatomo] [SPARK-3868][PySpark] Hard to recognize which module is tested from unit-tests.log