TST: io/netcdf: fix issues with warnings in tests
TST: io/netcdf: fix issues with warnings in tests

Ignore warning emitted in test_itemset_no_segfault_on_readonly.  Remove
a test using assert_warns; it doesn't clear warning registry, so the
warning in the other test makes this one not fire.

argriffing/scipy,mikebenfield/scipy,kleskjr/scipy,Srisai85/scipy,giorgiop/scipy,rmcgibbo/scipy,perimosocordiae/scipy,Gillu13/scipy,mtrbean/scipy,dominicelse/scipy,larsmans/scipy,jjhelmus/scipy,mortada/scipy,mingwpy/scipy,sauliusl/scipy,trankmichael/scipy,chatcannon/scipy,perimosocordiae/scipy,ChanderG/scipy,kleskjr/scipy,richardotis/scipy,trankmichael/scipy,Dapid/scipy,befelix/scipy,fredrikw/scipy,tylerjereddy/scipy,Stefan-Endres/scipy,surhudm/scipy,maniteja123/scipy,bkendzior/scipy,Dapid/scipy,zerothi/scipy,zerothi/scipy,rgommers/scipy,person142/scipy,haudren/scipy,surhudm/scipy,zerothi/scipy,fredrikw/scipy,witcxc/scipy,pschella/scipy,felipebetancur/scipy,matthewalbani/scipy,fernand/scipy,argriffing/scipy,rmcgibbo/scipy,nmayorov/scipy,ilayn/scipy,raoulbq/scipy,Shaswat27/scipy,aman-iitj/scipy,richardotis/scipy,jakevdp/scipy,larsmans/scipy,richardotis/scipy,aarchiba/scipy,scipy/scipy,gdooper/scipy,endolith/scipy,pnedunuri/scipy,grlee77/scipy,gef756/scipy,jsilter/scipy,sriki18/scipy,anielsen001/scipy,jonycgn/scipy,josephcslater/scipy,vigna/scipy,nvoron23/scipy,niknow/scipy,matthew-brett/scipy,sonnyhu/scipy,sauliusl/scipy,aeklant/scipy,Eric89GXL/scipy,jamestwebber/scipy,piyush0609/scipy,Gillu13/scipy,person142/scipy,piyush0609/scipy,bkendzior/scipy,argriffing/scipy,Srisai85/scipy,petebachant/scipy,cpaulik/scipy,jamestwebber/scipy,ChanderG/scipy,sonnyhu/scipy,minhlongdo/scipy,Kamp9/scipy,befelix/scipy,fernand/scipy,pschella/scipy,pnedunuri/scipy,andyfaff/scipy,bkendzior/scipy,Eric89GXL/scipy,nonhermitian/scipy,Gillu13/scipy,ortylp/scipy,behzadnouri/scipy,sonnyhu/scipy,felipebetancur/scipy,cpaulik/scipy,Eric89GXL/scipy,newemailjdm/scipy,person142/scipy,mgaitan/scipy,minhlongdo/scipy,jonycgn/scipy,ortylp/scipy,zxsted/scipy,pbrod/scipy,lukauskas/scipy,futurulus/scipy,maciejkula/scipy,vanpact/scipy,fredrikw/scipy,efiring/scipy,behzadnouri/scipy,mtrbean/scipy,grlee77/scipy,piyush0609/scipy,aarchiba/scipy,ndchorley/scipy,jsilter/scipy,raoulbq/scipy,futurulus/scipy,mdhaber/scipy,zxsted/scipy,ales-erjavec/scipy,raoulbq/scipy,zxsted/scipy,Gillu13/scipy,vhaasteren/scipy,befelix/scipy,chatcannon/scipy,gfyoung/scipy,jonycgn/scipy,aeklant/scipy,aarchiba/scipy,Newman101/scipy,haudren/scipy,pnedunuri/scipy,Stefan-Endres/scipy,lhilt/scipy,Newman101/scipy,surhudm/scipy,mortada/scipy,njwilson23/scipy,larsmans/scipy,mortonjt/scipy,felipebetancur/scipy,vanpact/scipy,newemailjdm/scipy,maniteja123/scipy,futurulus/scipy,pbrod/scipy,FRidh/scipy,apbard/scipy,mhogg/scipy,sriki18/scipy,apbard/scipy,vhaasteren/scipy,jakevdp/scipy,njwilson23/scipy,perimosocordiae/scipy,ilayn/scipy,vhaasteren/scipy,surhudm/scipy,gef756/scipy,efiring/scipy,WillieMaddox/scipy,Eric89GXL/scipy,gef756/scipy,gdooper/scipy,gfyoung/scipy,pyramania/scipy,mortada/scipy,jonycgn/scipy,anntzer/scipy,mdhaber/scipy,mdhaber/scipy,trankmichael/scipy,jjhelmus/scipy,aeklant/scipy,pnedunuri/scipy,jjhelmus/scipy,ndchorley/scipy,sauliusl/scipy,scipy/scipy,perimosocordiae/scipy,behzadnouri/scipy,gertingold/scipy,gdooper/scipy,behzadnouri/scipy,Dapid/scipy,raoulbq/scipy,ortylp/scipy,vigna/scipy,richardotis/scipy,witcxc/scipy,anntzer/scipy,anielsen001/scipy,grlee77/scipy,cpaulik/scipy,zaxliu/scipy,pizzathief/scipy,niknow/scipy,FRidh/scipy,hainm/scipy,endolith/scipy,mingwpy/scipy,piyush0609/scipy,felipebetancur/scipy,lhilt/scipy,nvoron23/scipy,WarrenWeckesser/scipy,jonycgn/scipy,sauliusl/scipy,FRidh/scipy,Kamp9/scipy,Shaswat27/scipy,chatcannon/scipy,mortada/scipy,jjhelmus/scipy,nmayorov/scipy,pnedunuri/scipy,dch312/scipy,Shaswat27/scipy,person142/scipy,zerothi/scipy,lhilt/scipy,kleskjr/scipy,matthew-brett/scipy,Stefan-Endres/scipy,tylerjereddy/scipy,pschella/scipy,nvoron23/scipy,futurulus/scipy,sonnyhu/scipy,gertingold/scipy,jjhelmus/scipy,futurulus/scipy,mortonjt/scipy,FRidh/scipy,ortylp/scipy,anntzer/scipy,apbard/scipy,zaxliu/scipy,gertingold/scipy,zxsted/scipy,anielsen001/scipy,perimosocordiae/scipy,mtrbean/scipy,maciejkula/scipy,maniteja123/scipy,maniteja123/scipy,kalvdans/scipy,sonnyhu/scipy,larsmans/scipy,Dapid/scipy,andim/scipy,aman-iitj/scipy,hainm/scipy,maciejkula/scipy,kleskjr/scipy,sriki18/scipy,jamestwebber/scipy,mortada/scipy,mhogg/scipy,witcxc/scipy,WarrenWeckesser/scipy,trankmichael/scipy,matthew-brett/scipy,nonhermitian/scipy,Kamp9/scipy,ChanderG/scipy,mingwpy/scipy,gdooper/scipy,dch312/scipy,ales-erjavec/scipy,jseabold/scipy,pizzathief/scipy,anntzer/scipy,mortonjt/scipy,vanpact/scipy,ortylp/scipy,sriki18/scipy,scipy/scipy,felipebetancur/scipy,haudren/scipy,Srisai85/scipy,jsilter/scipy,jsilter/scipy,jamestwebber/scipy,befelix/scipy,mikebenfield/scipy,jonycgn/scipy,WarrenWeckesser/scipy,anielsen001/scipy,giorgiop/scipy,rgommers/scipy,jseabold/scipy,WillieMaddox/scipy,mtrbean/scipy,josephcslater/scipy,zerothi/scipy,sauliusl/scipy,jor-/scipy,lhilt/scipy,ChanderG/scipy,petebachant/scipy,vberaudi/scipy,pschella/scipy,jseabold/scipy,jakevdp/scipy,rgommers/scipy,hainm/scipy,chatcannon/scipy,fernand/scipy,pyramania/scipy,woodscn/scipy,andyfaff/scipy,mtrbean/scipy,petebachant/scipy,newemailjdm/scipy,WillieMaddox/scipy,arokem/scipy,Shaswat27/scipy,WillieMaddox/scipy,maciejkula/scipy,jseabold/scipy,hainm/scipy,aarchiba/scipy,ChanderG/scipy,petebachant/scipy,mingwpy/scipy,ilayn/scipy,befelix/scipy,zxsted/scipy,zxsted/scipy,andim/scipy,aman-iitj/scipy,maniteja123/scipy,mortonjt/scipy,niknow/scipy,arokem/scipy,minhlongdo/scipy,trankmichael/scipy,haudren/scipy,nonhermitian/scipy,minhlongdo/scipy,fernand/scipy,nonhermitian/scipy,Kamp9/scipy,matthewalbani/scipy,fredrikw/scipy,jamestwebber/scipy,vberaudi/scipy,andim/scipy,ndchorley/scipy,ales-erjavec/scipy,jseabold/scipy,tylerjereddy/scipy,scipy/scipy,WarrenWeckesser/scipy,mikebenfield/scipy,andyfaff/scipy,vberaudi/scipy,gef756/scipy,petebachant/scipy,woodscn/scipy,cpaulik/scipy,dch312/scipy,newemailjdm/scipy,ChanderG/scipy,jakevdp/scipy,njwilson23/scipy,mingwpy/scipy,pyramania/scipy,dominicelse/scipy,cpaulik/scipy,surhudm/scipy,mortonjt/scipy,Newman101/scipy,argriffing/scipy,Dapid/scipy,anntzer/scipy,tylerjereddy/scipy,niknow/scipy,futurulus/scipy,ndchorley/scipy,pnedunuri/scipy,aarchiba/scipy,ilayn/scipy,Srisai85/scipy,larsmans/scipy,kalvdans/scipy,rmcgibbo/scipy,jor-/scipy,zaxliu/scipy,efiring/scipy,andim/scipy,andyfaff/scipy,kalvdans/scipy,arokem/scipy,surhudm/scipy,andim/scipy,pbrod/scipy,kalvdans/scipy,jakevdp/scipy,pizzathief/scipy,efiring/scipy,bkendzior/scipy,mikebenfield/scipy,vigna/scipy,e-q/scipy,jor-/scipy,apbard/scipy,sriki18/scipy,endolith/scipy,sauliusl/scipy,chatcannon/scipy,nmayorov/scipy,lukauskas/scipy,dominicelse/scipy,Gillu13/scipy,anielsen001/scipy,Eric89GXL/scipy,FRidh/scipy,lukauskas/scipy,e-q/scipy,dch312/scipy,pschella/scipy,aeklant/scipy,Gillu13/scipy,pyramania/scipy,zaxliu/scipy,pbrod/scipy,Dapid/scipy,mortada/scipy,mgaitan/scipy,richardotis/scipy,trankmichael/scipy,mgaitan/scipy,Newman101/scipy,vberaudi/scipy,zaxliu/scipy,gfyoung/scipy,mgaitan/scipy,Srisai85/scipy,jsilter/scipy,nmayorov/scipy,matthewalbani/scipy,piyush0609/scipy,e-q/scipy,jseabold/scipy,vanpact/scipy,WillieMaddox/scipy,woodscn/scipy,minhlongdo/scipy,mdhaber/scipy,behzadnouri/scipy,felipebetancur/scipy,lukauskas/scipy,gef756/scipy,njwilson23/scipy,sonnyhu/scipy,vanpact/scipy,gef756/scipy,matthewalbani/scipy,josephcslater/scipy,mgaitan/scipy,chatcannon/scipy,bkendzior/scipy,Newman101/scipy,argriffing/scipy,nvoron23/scipy,ales-erjavec/scipy,efiring/scipy,gertingold/scipy,Kamp9/scipy,haudren/scipy,pizzathief/scipy,lhilt/scipy,zerothi/scipy,endolith/scipy,rmcgibbo/scipy,minhlongdo/scipy,Stefan-Endres/scipy,gfyoung/scipy,Shaswat27/scipy,Kamp9/scipy,vhaasteren/scipy,zaxliu/scipy,grlee77/scipy,nvoron23/scipy,mdhaber/scipy,endolith/scipy,vigna/scipy,ilayn/scipy,raoulbq/scipy,anntzer/scipy,mtrbean/scipy,vhaasteren/scipy,nvoron23/scipy,niknow/scipy,mdhaber/scipy,richardotis/scipy,efiring/scipy,gfyoung/scipy,rgommers/scipy,fredrikw/scipy,jor-/scipy,ales-erjavec/scipy,dominicelse/scipy,nonhermitian/scipy,e-q/scipy,WarrenWeckesser/scipy,newemailjdm/scipy,vigna/scipy,josephcslater/scipy,matthew-brett/scipy,mhogg/scipy,arokem/scipy,sriki18/scipy,josephcslater/scipy,rmcgibbo/scipy,mortonjt/scipy,person142/scipy,witcxc/scipy,lukauskas/scipy,pizzathief/scipy,WillieMaddox/scipy,pbrod/scipy,maciejkula/scipy,gertingold/scipy,piyush0609/scipy,apbard/scipy,aman-iitj/scipy,arokem/scipy,mikebenfield/scipy,maniteja123/scipy,gdooper/scipy,Eric89GXL/scipy,behzadnouri/scipy,matthew-brett/scipy,scipy/scipy,nmayorov/scipy,woodscn/scipy,perimosocordiae/scipy,vberaudi/scipy,aeklant/scipy,Srisai85/scipy,fernand/scipy,andyfaff/scipy,witcxc/scipy,ales-erjavec/scipy,njwilson23/scipy,mhogg/scipy,andim/scipy,Stefan-Endres/scipy,matthewalbani/scipy,mhogg/scipy,WarrenWeckesser/scipy,Stefan-Endres/scipy,fredrikw/scipy,giorgiop/scipy,kleskjr/scipy,giorgiop/scipy,cpaulik/scipy,endolith/scipy,aman-iitj/scipy,giorgiop/scipy,niknow/scipy,larsmans/scipy,vhaasteren/scipy,pbrod/scipy,kalvdans/scipy,dch312/scipy,tylerjereddy/scipy,mhogg/scipy,hainm/scipy,petebachant/scipy,vberaudi/scipy,lukauskas/scipy,raoulbq/scipy,mgaitan/scipy,andyfaff/scipy,kleskjr/scipy,e-q/scipy,ndchorley/scipy,scipy/scipy,ilayn/scipy,fernand/scipy,woodscn/scipy,newemailjdm/scipy,rgommers/scipy,njwilson23/scipy,grlee77/scipy,anielsen001/scipy,argriffing/scipy,ortylp/scipy,pyramania/scipy,FRidh/scipy,mingwpy/scipy,Shaswat27/scipy,hainm/scipy,haudren/scipy,dominicelse/scipy,giorgiop/scipy,ndchorley/scipy,jor-/scipy,Newman101/scipy,rmcgibbo/scipy,woodscn/scipy,vanpact/scipy,aman-iitj/scipy