Wagyu creates spike geometry

Added a new test after extensive fuzzing that found a new failure case. The testcase has been added in the https://github.com/mapbox/wagyu/tree/spike_failure branch.

Resulting polygon with failure:


Original polygon from fuzzer:


Zoomed in:


Start with the testcase on the spike_failure branch and reproduce the polygon result shown in the issue. Trace the geometry operation that creates the spike and compare its output with the original polygon. Done means the testcase no longer produces spike geometry and the regression test passes.

Written by the indexing model from the issue text.