Fix unittests to support new implementation of KoPathShape::boundingRect

Two changes happened in KoPathShape::boundingRect after 9f6b70d3c0ee:

1. Shape has a stroke: then instead of tracing entire shape stroke and then calculating its bounds we just grow the outline of the shape by the insets of the stroke. It makes shapes manipulations much faster.

2. Shape has no stroke: then no outline growing happens. Before the commit, the outline was still traced with cosmetic 1px pen, so the bounding rect actually grew by 0.5px, which was not very correct (though harmless).