Revert "enable conv+bn folding for mixed-dtype when bn has post activation (#107142)"
This reverts commit 29813c61ea61d616230d3251ade81f56472ecb77.
Reverted https://github.com/pytorch/pytorch/pull/107142 on behalf of https://github.com/XiaobingSuper due to [Depends on reverted https://github.com/pytorch/pytorch/pull/106576](https://github.com/pytorch/pytorch/pull/106686) ([comment](https://github.com/pytorch/pytorch/pull/107142#issuecomment-1690968509))
