ConvexDecomposition asserts and invalid results

[helpsl]

When generating a decomposition in 2.86.1 it produces a few normalisation asserts and does not correctly decompose the object (Works in 2.85.1).

Looking at it line concavity.cpp:708 has been ifdef'd out to avoid a warning about an if(0.. statement.
However, there is an else statement which has also been included in this, which I assume wasn't meant to be.

[AndresTraks]

A great example of why consistent formatting is needed. :) #1007
It's pretty hard to follow an unformatted method that is also 225 lines long.