Make SHAPE_POLY_SET::CacheTriangulation() behavior same as previously.

Previously, SHAPE_POLY_SET::CacheTriangulation() was able to handle polygons
with holes.
Due to recent changes, CacheTriangulation( true ) handle polygons with holes,
but CacheTriangulation( false ) did not handle polygons with holes, due to a
missing call to Fracture(), lost in latest changes.
This is now fixed.

Fixes #5606
#5606

libs/kimath/src/geometry/shape_poly_set.cpp

@@ -1999,8 +1999,13 @@ void SHAPE_POLY_SET::CacheTriangulation( bool aPartition )
         // This partitions into regularly-sized grids (1cm in pcbnew)
         partitionPolyIntoRegularCellGrid( *this, 1e7, tmpSet );
     else
+    {
         tmpSet = *this;
 
+        if( tmpSet.HasHoles() )
+            tmpSet.Fracture( PM_FAST );
+    }
+
     m_triangulatedPolys.clear();
     m_triangulationValid = true;