Revert "Port `index.Tensor` to structured kernels."
This reverts commit 9fe6f1baf5d1c130e717fc32d993bb531ed05b62.
Reverted https://github.com/pytorch/pytorch/pull/69607 on behalf of https://github.com/suo due to this broke master, see: https://hud.pytorch.org/pytorch/pytorch/commit/9fe6f1baf5d1c130e717fc32d993bb531ed05b62
