This is the first test for a generic test suite for geometric functions.
The tests run are for fillet corners of SHAPE_POLY_SETS.
Previously, SHAPE_POLY_SET::Fillet was tested against CPolyLine::Fillet
to ensure compatibility. However, thse two functions now have different
interfaces and are not directly comparable. Also, this depended on
CPolyLine::Fillet being correct, which was not tested.
Instead, test SHAPE_POLY_SET::Fillet using tests against geometric
constraints, independent of any other fillet implementation.
265c882320