[PyTorch] Add C10_ALWAYS_INLINE to critical dispatcher paths (#51245)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/51245
Splitting this out from #51164 (D26069629) to allow it to
land separately; I'm sure this is a good idea but I'm less sure about
#51164.
ghstack-source-id: 120697499
Test Plan:
double-check effect on empty benchmark with perf stat;
didn't move
Reviweers: ezyang, messmer
Reviewed By: ezyang
Differential Revision: D26112627
fbshipit-source-id: 50d4418d351527bcedd5ccdc49106bc642699870
