This was removed in rB0666ece2e2f9 because it is handled differently for "real" cloth in cloth_solve_collisions(), but hair still needs this apparently [does its thing in cloth_continuum_step() instead]. And since we have a default 'Quality Steps' setting of 5, it made many simulations unstable. Fixes T65038, T59742 (possibly others) Reviewers: brecht Maniphest Tasks: T65038, T59742 Differential Revision: https://developer.blender.org/D5681