Object to Path broken when dynamic offset used

[Christopher M. Rogers]

Object to Path makes a bad conversion when offset is used on irregular shapes.

To reproduce:

1. Open Inkscape (current trunk)
2. Draw a rectangle
3. Draw a circle overlapping part of the rectangle
4. Combine the shapes (Path > Union)
5. Path > Dynamic Offset
6. Drag offset handle inwards or outwards a bit
7. Path > Object to Path

Result: Most of the nodes in the shape vanish, leaving only a small remnant of the original shape.

Note: This works fine on two rectangles, so i assume it's something to do with miscalculating offsets on curved shapes. Tried two circles, and they vanish entirely!

Inkscape 0.92.0+devel+201802131923 on Ubuntu 17.10

0.92.0+devel+201802110719 was the version that I had before this version. I think that's when it was still working.

[Alvin Penner (apenner)]

- problem not reproduced on Windows 10, Inkscape 0.92+devel (9d6b0e8, 2018-02-18)
- attached is the drawing I had after step 6

[Alvin Penner (apenner)]

attached is what I get after step 7

[Christopher M. Rogers (cajhne)]

Tav reverted a previous commit that has fixed it temporarily. I'm going to leave the bug open for now in case it helps him track down the problem. Thanks for the work everyone!