Opportunistically use __FILE_NAME__ to get filename (pytorch#19834) (pytorch#19834)

Summary:

The current approach use __FILE__ and opportunistically trims it if the
utility is available.

However, the long name is still stored in .rodata

This can contribute some memory on embedded platforms.


Instead, first try __FILE_NAME__

Differential Revision: D106587633

Author: JakeStevens