Remove THC ScalarConvert (#65471)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/65471
Test Plan: Imported from OSS
Reviewed By: H-Huang
Differential Revision: D31148182
Pulled By: ngimel
fbshipit-source-id: bbf74e36a3d91a7be3e47199981440c68a2f645f
