Get more descriptive errors from flaky test

[christiangnrd]

[only tests]

[maleadt]

Even though I'm not opposed to fixes like this, I feel like we need something more principled. All of the GPUArrays tests currently suffer from the same issue:

Error in testset gpuarrays/base:
Test Failed at /Users/tim/Julia/pkg/GPUArrays/test/testsuite/base.jl:274
  Expression: compare((x->begin
            #= /Users/tim/Julia/pkg/GPUArrays/test/testsuite/base.jl:274 =#
            circshift(x, (0, 1))
        end), AT, reshape(Vector(1:16), (4, 4)))

[christiangnrd]

Yeah this wasn't actually meant to be merged. However I forgot to edit the description or write any indication as such. It should probably be reverted once #442 is resolved but we might as well keep it for now since it allows our CI to pass instead of failing due to a bug that hasn't been reproduced locally.