[NFC] [C++20] [Modules] Remove pr60085.cppm with deprecated practice

See #60085 for the complete
story.

Previously I thought the problem got fixed surprisingly. But it is not
true. I just tested it with a deprecated method. My bad. Then the
deprecated style should be removed and the proper style can't work. So
I'll remove the test and reopen that issue to look into it.

Author: ChuanqiXu9