Blender Git Loki

Fix T80996: Weight Proximity modifier: crash going to editmode on a
target in certain situations

Regression from rBdeaff945d0b96.

mesh_ensure_looptri_data would overflow.

Crash would only happen if a Data Transfer modifier (transferring
UVs) follows, so exact reason for this is not yet entirely clear. Also
there are edit-mode versions of the following BVH lookup functions so it
could be avoided (since this is a expensive operation), marking as TODO.

Similar fix as
- rB0945a79ed1eafae444d3021a5912cb39801a7209
- rB56d7e39b92997768b3db8ce2dbc262f869994145

Reviewers: mont29, campbellbarton

Maniphest Tasks: T80996

Differential Revision: https://developer.blender.org/D8973