[TST] fix test_dtype_error to actually test what it's supposed to
[TST] fix test_dtype_error to actually test what it's supposed to

Discovered while cleaning up uses of the silly aliases like
'np.object'.

grlee77/numpy,gmcastil/numpy,skwbc/numpy,anntzer/numpy,mwiebe/numpy,kiwifb/numpy,charris/numpy,Eric89GXL/numpy,stuarteberg/numpy,AustereCuriosity/numpy,seberg/numpy,rgommers/numpy,gmcastil/numpy,mhvk/numpy,dwillmer/numpy,shoyer/numpy,Eric89GXL/numpy,shoyer/numpy,behzadnouri/numpy,pdebuyl/numpy,jorisvandenbossche/numpy,ddasilva/numpy,dwillmer/numpy,madphysicist/numpy,chiffa/numpy,endolith/numpy,endolith/numpy,drasmuss/numpy,grlee77/numpy,jorisvandenbossche/numpy,ahaldane/numpy,pbrod/numpy,bringingheavendown/numpy,jonathanunderwood/numpy,MSeifert04/numpy,numpy/numpy,simongibbons/numpy,charris/numpy,shoyer/numpy,MSeifert04/numpy,simongibbons/numpy,grlee77/numpy,MSeifert04/numpy,behzadnouri/numpy,abalkin/numpy,nbeaver/numpy,ddasilva/numpy,maniteja123/numpy,pbrod/numpy,mattip/numpy,pdebuyl/numpy,jorisvandenbossche/numpy,WarrenWeckesser/numpy,ahaldane/numpy,jorisvandenbossche/numpy,utke1/numpy,WarrenWeckesser/numpy,pizzathief/numpy,bertrand-l/numpy,joferkington/numpy,jonathanunderwood/numpy,gmcastil/numpy,mhvk/numpy,drasmuss/numpy,maniteja123/numpy,tynn/numpy,tacaswell/numpy,seberg/numpy,bringingheavendown/numpy,anntzer/numpy,utke1/numpy,ahaldane/numpy,Dapid/numpy,pizzathief/numpy,jakirkham/numpy,pizzathief/numpy,numpy/numpy,Dapid/numpy,rherault-insa/numpy,ahaldane/numpy,rgommers/numpy,rgommers/numpy,gfyoung/numpy,SiccarPoint/numpy,bertrand-l/numpy,stuarteberg/numpy,ESSS/numpy,ddasilva/numpy,dwillmer/numpy,ssanderson/numpy,pizzathief/numpy,charris/numpy,pdebuyl/numpy,ahaldane/numpy,kiwifb/numpy,MSeifert04/numpy,AustereCuriosity/numpy,mattip/numpy,madphysicist/numpy,mhvk/numpy,SiccarPoint/numpy,grlee77/numpy,skwbc/numpy,behzadnouri/numpy,anntzer/numpy,pizzathief/numpy,jakirkham/numpy,anntzer/numpy,WarrenWeckesser/numpy,argriffing/numpy,rherault-insa/numpy,pbrod/numpy,endolith/numpy,ESSS/numpy,mhvk/numpy,seberg/numpy,mattip/numpy,simongibbons/numpy,numpy/numpy,kiwifb/numpy,b-carter/numpy,endolith/numpy,madphysicist/numpy,mhvk/numpy,tynn/numpy,b-carter/numpy,argriffing/numpy,pdebuyl/numpy,ESSS/numpy,jakirkham/numpy,utke1/numpy,nbeaver/numpy,Eric89GXL/numpy,ssanderson/numpy,chatcannon/numpy,chatcannon/numpy,tacaswell/numpy,ContinuumIO/numpy,solarjoe/numpy,ContinuumIO/numpy,grlee77/numpy,njase/numpy,numpy/numpy,bertrand-l/numpy,jakirkham/numpy,SiccarPoint/numpy,joferkington/numpy,solarjoe/numpy,jorisvandenbossche/numpy,abalkin/numpy,argriffing/numpy,jakirkham/numpy,jonathanunderwood/numpy,pbrod/numpy,WarrenWeckesser/numpy,ssanderson/numpy,njase/numpy,bringingheavendown/numpy,chiffa/numpy,gfyoung/numpy,rherault-insa/numpy,gfyoung/numpy,drasmuss/numpy,AustereCuriosity/numpy,simongibbons/numpy,b-carter/numpy,tacaswell/numpy,stuarteberg/numpy,pbrod/numpy,rgommers/numpy,dwillmer/numpy,skwbc/numpy,shoyer/numpy,njase/numpy,nbeaver/numpy,solarjoe/numpy,joferkington/numpy,chatcannon/numpy,abalkin/numpy,MSeifert04/numpy,madphysicist/numpy,charris/numpy,joferkington/numpy,simongibbons/numpy,mwiebe/numpy,stuarteberg/numpy,maniteja123/numpy,madphysicist/numpy,SiccarPoint/numpy,Dapid/numpy,shoyer/numpy,chiffa/numpy,seberg/numpy,ContinuumIO/numpy,Eric89GXL/numpy,WarrenWeckesser/numpy,mattip/numpy,tynn/numpy,mwiebe/numpy