TST: Ensure `like=` tests are not sensitive to execution order
TST: Ensure `like=` tests are not sensitive to execution order

This moves class creation into a `setup` function and uses `self`
instead of the test class all over.  There are probably nicer
ways to fix (and improve) it, but this seemed nice minimal.

numpy/numpy,jakirkham/numpy,mattip/numpy,anntzer/numpy,seberg/numpy,pbrod/numpy,mhvk/numpy,mhvk/numpy,simongibbons/numpy,pdebuyl/numpy,mattip/numpy,seberg/numpy,numpy/numpy,pbrod/numpy,anntzer/numpy,numpy/numpy,anntzer/numpy,jakirkham/numpy,pbrod/numpy,seberg/numpy,rgommers/numpy,jakirkham/numpy,madphysicist/numpy,rgommers/numpy,simongibbons/numpy,madphysicist/numpy,rgommers/numpy,anntzer/numpy,mhvk/numpy,endolith/numpy,endolith/numpy,mhvk/numpy,endolith/numpy,madphysicist/numpy,pdebuyl/numpy,pdebuyl/numpy,simongibbons/numpy,jakirkham/numpy,rgommers/numpy,pbrod/numpy,numpy/numpy,pdebuyl/numpy,charris/numpy,mattip/numpy,endolith/numpy,pbrod/numpy,seberg/numpy,charris/numpy,jakirkham/numpy,madphysicist/numpy,charris/numpy,madphysicist/numpy,mattip/numpy,mhvk/numpy,simongibbons/numpy,simongibbons/numpy,charris/numpy