update tests for consistent to_value behavior
update tests for consistent to_value behavior

saimn/astropy,aleksandr-bakanov/astropy,mhvk/astropy,dhomeier/astropy,lpsinger/astropy,mhvk/astropy,astropy/astropy,astropy/astropy,StuartLittlefair/astropy,aleksandr-bakanov/astropy,astropy/astropy,pllim/astropy,larrybradley/astropy,lpsinger/astropy,aleksandr-bakanov/astropy,stargaser/astropy,dhomeier/astropy,larrybradley/astropy,pllim/astropy,dhomeier/astropy,pllim/astropy,StuartLittlefair/astropy,mhvk/astropy,mhvk/astropy,mhvk/astropy,lpsinger/astropy,MSeifert04/astropy,astropy/astropy,astropy/astropy,pllim/astropy,saimn/astropy,dhomeier/astropy,lpsinger/astropy,saimn/astropy,dhomeier/astropy,MSeifert04/astropy,larrybradley/astropy,saimn/astropy,lpsinger/astropy,stargaser/astropy,StuartLittlefair/astropy,saimn/astropy,StuartLittlefair/astropy,aleksandr-bakanov/astropy,StuartLittlefair/astropy,larrybradley/astropy,MSeifert04/astropy,MSeifert04/astropy,larrybradley/astropy,stargaser/astropy,stargaser/astropy,pllim/astropy