This addresses warnings from Clang-Tidy's `readability-else-after-return`
rule in the `source/blender/blenkernel` module. Not all warnings are
addressed in this commit.
No functional changes.
This is an improvement over 2.7x which converted edit-mesh to mesh
(CDDM) for all 3 modifiers.
Overall this increases performance in edit-mode by around 15-20%.
