Does turbulent flow encourage/avert flow separation?
Turbulence delays flow separation. This is why we attempt vortex generators and turbulators in aerodynamic design when local flow separation is an issue.

A. Adverse Pressure Gradient

Fundamental to the generation of subsonic lift, as airflow accelerates over the leading edge, its pressure drops, resulting in net suction. At some point, usually corresponding to the point of re-converging airfoil geometry, the flow begins to decelerate as its pressure rises, eventually equating to the flow pressure on the lower surface at the trailing edge. This process is called pressure recovery, and the increasing pressure profile along the upper surface is called adverse pressure gradient.



Image modified from: https://conself.com/blog/calculate-lift-drag-with-paraview/

B. Laminar Boundary Layer

Within the boundary layer, which is a thin envelope flow close to the airfoil surface, an adverse pressure gradient in the external flow can slow the flow close to the surface (which is already much slower than the external flow due to no-slip condition) to a standstill. At that point, the separation occurs. This is more or less the story with laminar boundary layer where the flow is smooth.



Image ref: https://en.wikipedia.org/wiki/Flow_separation#/media/File:Boundary_layer_separation.svg

C. Turbulent Boundary Layer

Now in the case of a turbulent boundary layer, there is a lot more mixing going on within the boundary layer due to eddies. As a result, there is continued energy injection into the bottom layer flows, which delays the flow separation that would normally occur in a laminar boundary layer. 



Image ref: http://www.bakker.org/dartmouth06/engs150/11-bl.pdf