Revert "fallback for scatter_(scalar) (#88210)"
This reverts commit 896fa8c5c9b0191c9621e04ab5e20057614d48ad.
Reverted https://github.com/pytorch/pytorch/pull/88210 on behalf of https://github.com/suo due to this broke inductor tests, see: https://hud.pytorch.org/pytorch/pytorch/commit/896fa8c5c9b0191c9621e04ab5e20057614d48ad
