In order to handle 'cairo-perf-trace benchmark', we need to perform the
can_run? test on the directory name as opposed to the individual trace
names. Make it so.
Use cairo_stroke() to perform the equivalent of
spiral-rect-(pix|non)align-evenodd-fill. A useful comparison of stroking
versus filling, as we can assume the composition costs are similar.
Oops we were accumulating paths during each spiral iteration and so the
tests were getting slower and slower and slower...
[And fix a couple of other instances of path accumulation.]
By ensuring that tests take longer than a couple of seconds we eliminate
systematic errors in our measurements. However, we also effectively
eliminate the synchronisation overhead. To compensate, we attempt to
estimate the overhead by reporting the difference between a single
instance and the minimum averaged instance.
These tests look at the differences in code paths
hit by filling paths that are rectilinear (or not) and
pixel aligned (or not) with the even-odd and non-zero
fill rules. The paths are not simple, so they don't
hit the special case quad/triangle tessellator.
