8176501: Method Shape.getBounds2D() incorrectly includes Bezier control points in bounding box

This is broadly addresses the code review feedback: "I see many duplicated lines". This commit does NOT include "the previous unified solution" that is also mentioned... so we'll try this on and see how we feel about it.

https://github.com/openjdk/jdk/pull/6227#issuecomment-964020449