Exposed by bc0b86797c
(but even before we had Asserts in a debug build -- also crashed
WITH_ASSERT_ABORT OFF)
The call to ensure Mesh data from a mesh in edit mode needs
to happen before the triangulation which uses Mesh. This gets rid of
the crash and also previous asserts.
Pull Request: https://projects.blender.org/blender/blender/pulls/133859