Revert D23549149: [PyTorch][Mobile] Insert the module name as `name()` to metadata dict if metadata doesn't contain "model_name"
Test Plan: revert-hammer
Differential Revision:
D23549149 (https://github.com/pytorch/pytorch/commit/398409f07284cad25c500cc252518bbbf78f672e)
Original commit changeset: fad742a8d4e6
fbshipit-source-id: bd92a2033a804d3e6a2747b4fda4ca527991a993
