💾 trunk/1f159f1d33b4d6042cc00743cf0228c6eb44cb0f: Revert "Use C++20 default member initializers for bit-fields (#183992)"

This reverts commit 1ac76df.
Reverted #183992 on behalf of https://github.com/pytorch-auto-revert due to Reverted automatically by pytorch's autorevert, to avoid this behaviour add the tag autorevert: disable (comment)