Some microwave inductor lengths cause invalid outputs
for the calculations, which causes jagged outputs.
* If the request length is such that four arcs and no straight
segments is too long
* If the length is such that an N-turn coil is too short, but
an N+1-turn coil is too long. This can happen when the coil
count is small.
This patch doesn't fix the underlying geometric issue here - fixing
the first requires a numerical method, and fixing the second probably
needs an iterative approach. Both of these could benefit from
a refactor.
However, this patch does prevent the tools producing invalid outputs,
which can sometimes be quite subtle mistakes if the "jags" are small.
Fixes: lp:1792119
* https://bugs.launchpad.net/kicad/+bug/1792119
d39cdb5565