Revert checkpoint tmp dir (#36112)
* Revert "Fix OS err (#36094)"
This reverts commit ba29a439adbe6f371710d0514659127264ae24b3.
* Revert "Save checkpoint to temporary directory to handle partial saves during failures (#35580)"
This reverts commit 20d17358c468b7aefca9e54c3461eb88d1ee34f9.
