Add DimType info in dumped debug nets (#26589)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/26589
Just for better debugging purpose.
Test Plan: Dump the net and check the dim type info is in the pb_txt.
Reviewed By: dreamingleo
Differential Revision: D17505931
fbshipit-source-id: ceba4c3849eb271c22227fa07a05d5bcb07344a5
