Fixesflutter/flutter#13018
When linear blending was disabled, we started rendering directly to FBO0 again. We can't attach stencil there, and the profile graph code triggers a path that (by default) uses it. This option forces us to use alternate rendering methods.
Note that the graph rendering code is constructing a fairly complex path. It would probably be much faster to render as a simpler series of drawRect calls for each box (which would get batched inside Skia).