Auto merge of #119677 - cjgillot:early-cfg-opt, r=oli-obk

Reorder early post-inlining passes.

`RemoveZsts`, `RemoveUnneededDrops` and `UninhabitedEnumBranching` only depend on types, so they should be executed together early after MIR inlining introduces those types.

This does not change the end-result, but this makes the pipeline a bit more consistent.

Author: bors