7f6ffe9195
It's an explicit check to prevent division by zero if caller hasn't
done the check. Future patch {D8867} will not use the nla remap
function and thus not do the check. This patch also replaces some
float (==) equality checks with IS_EQF().
Split from {D9247}
Reviewed By: sybren
Differential Revision: https://developer.blender.org/D9694