Blender Git Loki

Enabled workaround to solve threading issues in draw manager

This workaround addresses T79533 and T79038 for Blender 2.90. The
solution isn't clear and needs more research and work. In order to
continue with blender 2.90 release it was proposed to add this work
around.

It has been tested with the test files provided in the reports.

Reviewed By: Dalai Felinto, Cl�ment Foucault

Differential Revision: https://developer.blender.org/D8695