Revert "add int8 packed gemm support on CPU device (#118056)"
This reverts commit f84375ca5db623a6a53cbce2864d27dfad626228.
Reverted https://github.com/pytorch/pytorch/pull/118056 on behalf of https://github.com/izaitsevfb due to breaks internal builds ([comment](https://github.com/pytorch/pytorch/pull/118056#issuecomment-1977368720))
