Revert "Add fast path of qmean/qstd for quantized CPU (#70172)"
This reverts commit c1fa9fdff9dc79557767bee23c66dcaa4095300c.
Reverted https://github.com/pytorch/pytorch/pull/70172 on behalf of https://github.com/suo due to broke windows builds, see: https://hud.pytorch.org/pytorch/pytorch/commit/c1fa9fdff9dc79557767bee23c66dcaa4095300c
