Bug#892288: arrayfire test crash

[Rebecca N. Palmer]

Control: tags -1 fixed-upstream patch

These look like the upstream fixes, though I haven't actually tried them 
yet.

for index:

https://github.com/arrayfire/arrayfire/commit/58ac59497b50257631713e689a6b0ddffb73361a

for assign:

https://github.com/arrayfire/arrayfire/commit/1b18226dfec811e4b7b7254f5cfc85a3116a3dc2