Changed astropy/tests/helper.py imports to relative imports.
Changed astropy/tests/helper.py imports to relative imports.

dhomeier/astropy,stargaser/astropy,astropy/astropy,stargaser/astropy,tbabej/astropy,dhomeier/astropy,tbabej/astropy,AustereCuriosity/astropy,AustereCuriosity/astropy,kelle/astropy,astropy/astropy,DougBurke/astropy,pllim/astropy,kelle/astropy,saimn/astropy,mhvk/astropy,lpsinger/astropy,larrybradley/astropy,kelle/astropy,mhvk/astropy,saimn/astropy,MSeifert04/astropy,pllim/astropy,pllim/astropy,AustereCuriosity/astropy,lpsinger/astropy,MSeifert04/astropy,mhvk/astropy,dhomeier/astropy,StuartLittlefair/astropy,larrybradley/astropy,joergdietrich/astropy,stargaser/astropy,StuartLittlefair/astropy,StuartLittlefair/astropy,joergdietrich/astropy,funbaker/astropy,aleksandr-bakanov/astropy,funbaker/astropy,DougBurke/astropy,MSeifert04/astropy,dhomeier/astropy,kelle/astropy,DougBurke/astropy,mhvk/astropy,bsipocz/astropy,tbabej/astropy,AustereCuriosity/astropy,joergdietrich/astropy,joergdietrich/astropy,astropy/astropy,mhvk/astropy,astropy/astropy,StuartLittlefair/astropy,bsipocz/astropy,lpsinger/astropy,aleksandr-bakanov/astropy,AustereCuriosity/astropy,larrybradley/astropy,pllim/astropy,saimn/astropy,StuartLittlefair/astropy,saimn/astropy,bsipocz/astropy,larrybradley/astropy,stargaser/astropy,lpsinger/astropy,tbabej/astropy,saimn/astropy,MSeifert04/astropy,funbaker/astropy,lpsinger/astropy,dhomeier/astropy,DougBurke/astropy,larrybradley/astropy,astropy/astropy,aleksandr-bakanov/astropy,funbaker/astropy,joergdietrich/astropy,kelle/astropy,aleksandr-bakanov/astropy,pllim/astropy,bsipocz/astropy,tbabej/astropy