Back out "[pytorch][PR] don't materialize constants" (#21374)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/21374
Original commit changeset: d5609b0a5697
Not materializing constants slows compilation time significantly
Differential Revision: D15630632
fbshipit-source-id: c6b5026ee6eae2ef290628f350f49a657495bd5d
