remove aliasMultinomial decode from TH and THC (#52585)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/52585
Test Plan: Imported from OSS
Reviewed By: ailzhang
Differential Revision: D26654125
Pulled By: albanD
fbshipit-source-id: 6a745080021623a2472dae7862cde91b949983ee
