Remove preallocation of type ids (#28024)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/28024
We preallocated type ids to align them with ScalarType. At that point, the maximum type id was 10 and we used 11 to specify undefined type id.
However, since then, ScalarType got more additions, 11 isn't undefined anymore, and numbers 11-15 have meaning.
caffe2::TypeIdentifier also got its separate additions, 12 and upwards have meaning that differs from ScalarType.
I'm going with the (CI-tested) assumption that caffe2::TypeIdentifier and ScalarType actually don't need to be aligned
and remove the functionality for preallocated type ids. This simplifies our type ids.
ghstack-source-id: 92051872
Test Plan: unit tests
Differential Revision: D17936165
fbshipit-source-id: 2c9df2b9b3f35b3e319641c96638321ac3433d5c
