Add test coverage for gpr_refn() function
Add test coverage for gpr_refn() function

grpc/grpc,ctiller/grpc,ejona86/grpc,donnadionne/grpc,fuchsia-mirror/third_party-grpc,stanley-cheung/grpc,goldenbull/grpc,yang-g/grpc,vsco/grpc,mehrdada/grpc,tengyifei/grpc,daniel-j-born/grpc,deepaklukose/grpc,vjpai/grpc,geffzhang/grpc,tengyifei/grpc,ejona86/grpc,thunderboltsid/grpc,msiedlarek/grpc,y-zeng/grpc,tengyifei/grpc,bogdandrutu/grpc,podsvirov/grpc,carl-mastrangelo/grpc,LuminateWireless/grpc,msmania/grpc,geffzhang/grpc,kriswuollett/grpc,ejona86/grpc,ejona86/grpc,pszemus/grpc,apolcyn/grpc,ananthonline/grpc,ctiller/grpc,Vizerai/grpc,arkmaxim/grpc,quizlet/grpc,goldenbull/grpc,infinit/grpc,LuminateWireless/grpc,infinit/grpc,y-zeng/grpc,ctiller/grpc,geffzhang/grpc,ipylypiv/grpc,ejona86/grpc,ncteisen/grpc,kpayson64/grpc,nicolasnoble/grpc,a11r/grpc,murgatroid99/grpc,grpc/grpc,adelez/grpc,zhimingxie/grpc,yugui/grpc,ppietrasa/grpc,msmania/grpc,daniel-j-born/grpc,grpc/grpc,maxwell-demon/grpc,Crevil/grpc,perumaalgoog/grpc,dklempner/grpc,stanley-cheung/grpc,kriswuollett/grpc,simonkuang/grpc,msmania/grpc,y-zeng/grpc,muxi/grpc,chrisdunelm/grpc,firebase/grpc,makdharma/grpc,donnadionne/grpc,ipylypiv/grpc,ppietrasa/grpc,ctiller/grpc,murgatroid99/grpc,mehrdada/grpc,PeterFaiman/ruby-grpc-minimal,greasypizza/grpc,ejona86/grpc,a-veitch/grpc,podsvirov/grpc,y-zeng/grpc,yugui/grpc,ctiller/grpc,7anner/grpc,soltanmm/grpc,hstefan/grpc,tamihiro/grpc,LuminateWireless/grpc,msiedlarek/grpc,makdharma/grpc,malexzx/grpc,VcamX/grpc,jcanizales/grpc,deepaklukose/grpc,thinkerou/grpc,thunderboltsid/grpc,andrewpollock/grpc,Crevil/grpc,ctiller/grpc,makdharma/grpc,mehrdada/grpc,miselin/grpc,hstefan/grpc,tamihiro/grpc,bogdandrutu/grpc,soltanmm-google/grpc,greasypizza/grpc,wcevans/grpc,zhimingxie/grpc,grpc/grpc,andrewpollock/grpc,simonkuang/grpc,hstefan/grpc,goldenbull/grpc,tamihiro/grpc,yongni/grpc,rjshade/grpc,greasypizza/grpc,tengyifei/grpc,yang-g/grpc,Vizerai/grpc,kumaralokgithub/grpc,7anner/grpc,ppietrasa/grpc,kriswuollett/grpc,perumaalgoog/grpc,pmarks-net/grpc,philcleveland/grpc,yugui/grpc,dklempner/grpc,rjshade/grpc,grpc/grpc,kpayson64/grpc,VcamX/grpc,philcleveland/grpc,firebase/grpc,PeterFaiman/ruby-grpc-minimal,miselin/grpc,yongni/grpc,ipylypiv/grpc,thunderboltsid/grpc,thinkerou/grpc,jboeuf/grpc,quizlet/grpc,nicolasnoble/grpc,jboeuf/grpc,donnadionne/grpc,greasypizza/grpc,hstefan/grpc,soltanmm-google/grpc,pmarks-net/grpc,sreecha/grpc,yang-g/grpc,carl-mastrangelo/grpc,makdharma/grpc,yang-g/grpc,chrisdunelm/grpc,baylabs/grpc,kumaralokgithub/grpc,muxi/grpc,wcevans/grpc,greasypizza/grpc,jtattermusch/grpc,ctiller/grpc,bogdandrutu/grpc,a-veitch/grpc,mehrdada/grpc,soltanmm/grpc,pszemus/grpc,dgquintas/grpc,goldenbull/grpc,PeterFaiman/ruby-grpc-minimal,goldenbull/grpc,kpayson64/grpc,wcevans/grpc,msiedlarek/grpc,ananthonline/grpc,jtattermusch/grpc,a-veitch/grpc,adelez/grpc,stanley-cheung/grpc,vsco/grpc,rjshade/grpc,thunderboltsid/grpc,deepaklukose/grpc,royalharsh/grpc,fuchsia-mirror/third_party-grpc,fuchsia-mirror/third_party-grpc,kumaralokgithub/grpc,baylabs/grpc,dgquintas/grpc,sreecha/grpc,dklempner/grpc,7anner/grpc,rjshade/grpc,greasypizza/grpc,goldenbull/grpc,apolcyn/grpc,sreecha/grpc,deepaklukose/grpc,Crevil/grpc,kpayson64/grpc,daniel-j-born/grpc,dgquintas/grpc,dklempner/grpc,vsco/grpc,y-zeng/grpc,tamihiro/grpc,ananthonline/grpc,tamihiro/grpc,adelez/grpc,LuminateWireless/grpc,wcevans/grpc,kriswuollett/grpc,greasypizza/grpc,fuchsia-mirror/third_party-grpc,jtattermusch/grpc,nicolasnoble/grpc,miselin/grpc,VcamX/grpc,grpc/grpc,ncteisen/grpc,perumaalgoog/grpc,LuminateWireless/grpc,firebase/grpc,a11r/grpc,wcevans/grpc,Crevil/grpc,royalharsh/grpc,MakMukhi/grpc,arkmaxim/grpc,Vizerai/grpc,Vizerai/grpc,dgquintas/grpc,soltanmm-google/grpc,a11r/grpc,VcamX/grpc,ncteisen/grpc,nicolasnoble/grpc,kskalski/grpc,carl-mastrangelo/grpc,jcanizales/grpc,VcamX/grpc,a-veitch/grpc,MakMukhi/grpc,dklempner/grpc,y-zeng/grpc,jcanizales/grpc,donnadionne/grpc,Vizerai/grpc,vsco/grpc,sreecha/grpc,leifurhauks/grpc,philcleveland/grpc,chrisdunelm/grpc,thinkerou/grpc,goldenbull/grpc,andrewpollock/grpc,matt-kwong/grpc,firebase/grpc,rjshade/grpc,tamihiro/grpc,royalharsh/grpc,carl-mastrangelo/grpc,MakMukhi/grpc,ananthonline/grpc,pszemus/grpc,a11r/grpc,PeterFaiman/ruby-grpc-minimal,donnadionne/grpc,infinit/grpc,kumaralokgithub/grpc,stanley-cheung/grpc,yongni/grpc,baylabs/grpc,miselin/grpc,vjpai/grpc,vsco/grpc,ppietrasa/grpc,maxwell-demon/grpc,pszemus/grpc,matt-kwong/grpc,y-zeng/grpc,nicolasnoble/grpc,dgquintas/grpc,pszemus/grpc,grpc/grpc,stanley-cheung/grpc,baylabs/grpc,zhimingxie/grpc,tamihiro/grpc,royalharsh/grpc,stanley-cheung/grpc,kskalski/grpc,PeterFaiman/ruby-grpc-minimal,a-veitch/grpc,grani/grpc,makdharma/grpc,msmania/grpc,thinkerou/grpc,malexzx/grpc,philcleveland/grpc,leifurhauks/grpc,adelez/grpc,leifurhauks/grpc,murgatroid99/grpc,yang-g/grpc,MakMukhi/grpc,muxi/grpc,kskalski/grpc,soltanmm-google/grpc,infinit/grpc,ncteisen/grpc,PeterFaiman/ruby-grpc-minimal,goldenbull/grpc,mehrdada/grpc,miselin/grpc,simonkuang/grpc,rjshade/grpc,hstefan/grpc,andrewpollock/grpc,muxi/grpc,7anner/grpc,jcanizales/grpc,kumaralokgithub/grpc,perumaalgoog/grpc,murgatroid99/grpc,chrisdunelm/grpc,pszemus/grpc,jboeuf/grpc,maxwell-demon/grpc,simonkuang/grpc,bogdandrutu/grpc,vjpai/grpc,dklempner/grpc,bogdandrutu/grpc,thinkerou/grpc,baylabs/grpc,a11r/grpc,philcleveland/grpc,kriswuollett/grpc,adelez/grpc,daniel-j-born/grpc,kskalski/grpc,podsvirov/grpc,maxwell-demon/grpc,MakMukhi/grpc,jboeuf/grpc,mehrdada/grpc,grani/grpc,vsco/grpc,makdharma/grpc,podsvirov/grpc,firebase/grpc,yongni/grpc,soltanmm/grpc,grani/grpc,ctiller/grpc,sreecha/grpc,jboeuf/grpc,nicolasnoble/grpc,yongni/grpc,yugui/grpc,hstefan/grpc,zhimingxie/grpc,arkmaxim/grpc,Crevil/grpc,maxwell-demon/grpc,chrisdunelm/grpc,jtattermusch/grpc,arkmaxim/grpc,kskalski/grpc,vsco/grpc,quizlet/grpc,kumaralokgithub/grpc,donnadionne/grpc,philcleveland/grpc,tamihiro/grpc,dgquintas/grpc,kskalski/grpc,pszemus/grpc,malexzx/grpc,geffzhang/grpc,daniel-j-born/grpc,msiedlarek/grpc,infinit/grpc,daniel-j-born/grpc,rjshade/grpc,a11r/grpc,thinkerou/grpc,thunderboltsid/grpc,mehrdada/grpc,Vizerai/grpc,ananthonline/grpc,pmarks-net/grpc,royalharsh/grpc,perumaalgoog/grpc,carl-mastrangelo/grpc,ncteisen/grpc,muxi/grpc,jtattermusch/grpc,zhimingxie/grpc,firebase/grpc,maxwell-demon/grpc,thinkerou/grpc,ejona86/grpc,chrisdunelm/grpc,ppietrasa/grpc,a-veitch/grpc,grpc/grpc,carl-mastrangelo/grpc,infinit/grpc,msiedlarek/grpc,mehrdada/grpc,wcevans/grpc,philcleveland/grpc,wcevans/grpc,leifurhauks/grpc,msiedlarek/grpc,jboeuf/grpc,grani/grpc,bogdandrutu/grpc,grani/grpc,kriswuollett/grpc,soltanmm/grpc,kpayson64/grpc,philcleveland/grpc,yongni/grpc,deepaklukose/grpc,firebase/grpc,jcanizales/grpc,PeterFaiman/ruby-grpc-minimal,a11r/grpc,vjpai/grpc,carl-mastrangelo/grpc,nicolasnoble/grpc,jtattermusch/grpc,vjpai/grpc,7anner/grpc,kskalski/grpc,thinkerou/grpc,philcleveland/grpc,ananthonline/grpc,firebase/grpc,jboeuf/grpc,ejona86/grpc,matt-kwong/grpc,malexzx/grpc,kpayson64/grpc,chrisdunelm/grpc,soltanmm-google/grpc,7anner/grpc,ejona86/grpc,Vizerai/grpc,kpayson64/grpc,nicolasnoble/grpc,Vizerai/grpc,baylabs/grpc,apolcyn/grpc,jboeuf/grpc,murgatroid99/grpc,soltanmm/grpc,jcanizales/grpc,miselin/grpc,VcamX/grpc,jtattermusch/grpc,nicolasnoble/grpc,podsvirov/grpc,ctiller/grpc,kumaralokgithub/grpc,sreecha/grpc,infinit/grpc,yugui/grpc,ananthonline/grpc,Crevil/grpc,kpayson64/grpc,Crevil/grpc,kumaralokgithub/grpc,matt-kwong/grpc,deepaklukose/grpc,dgquintas/grpc,dgquintas/grpc,pszemus/grpc,maxwell-demon/grpc,andrewpollock/grpc,vsco/grpc,yugui/grpc,maxwell-demon/grpc,stanley-cheung/grpc,Vizerai/grpc,donnadionne/grpc,muxi/grpc,sreecha/grpc,arkmaxim/grpc,VcamX/grpc,stanley-cheung/grpc,stanley-cheung/grpc,a11r/grpc,tengyifei/grpc,malexzx/grpc,donnadionne/grpc,andrewpollock/grpc,apolcyn/grpc,makdharma/grpc,7anner/grpc,nicolasnoble/grpc,soltanmm/grpc,leifurhauks/grpc,royalharsh/grpc,murgatroid99/grpc,a-veitch/grpc,podsvirov/grpc,chrisdunelm/grpc,yugui/grpc,ncteisen/grpc,vjpai/grpc,murgatroid99/grpc,quizlet/grpc,PeterFaiman/ruby-grpc-minimal,muxi/grpc,msiedlarek/grpc,infinit/grpc,ipylypiv/grpc,hstefan/grpc,soltanmm-google/grpc,donnadionne/grpc,pmarks-net/grpc,firebase/grpc,Vizerai/grpc,yang-g/grpc,bogdandrutu/grpc,simonkuang/grpc,simonkuang/grpc,ejona86/grpc,baylabs/grpc,pmarks-net/grpc,simonkuang/grpc,quizlet/grpc,fuchsia-mirror/third_party-grpc,vjpai/grpc,a-veitch/grpc,yang-g/grpc,tengyifei/grpc,y-zeng/grpc,msmania/grpc,msmania/grpc,mehrdada/grpc,chrisdunelm/grpc,chrisdunelm/grpc,muxi/grpc,mehrdada/grpc,maxwell-demon/grpc,mehrdada/grpc,firebase/grpc,fuchsia-mirror/third_party-grpc,dgquintas/grpc,LuminateWireless/grpc,grpc/grpc,LuminateWireless/grpc,leifurhauks/grpc,wcevans/grpc,Vizerai/grpc,yang-g/grpc,muxi/grpc,yongni/grpc,soltanmm-google/grpc,vsco/grpc,geffzhang/grpc,stanley-cheung/grpc,quizlet/grpc,malexzx/grpc,daniel-j-born/grpc,muxi/grpc,apolcyn/grpc,ananthonline/grpc,miselin/grpc,yongni/grpc,ncteisen/grpc,murgatroid99/grpc,ctiller/grpc,msiedlarek/grpc,y-zeng/grpc,carl-mastrangelo/grpc,soltanmm/grpc,grani/grpc,greasypizza/grpc,ppietrasa/grpc,pszemus/grpc,msiedlarek/grpc,thunderboltsid/grpc,ctiller/grpc,adelez/grpc,geffzhang/grpc,grani/grpc,baylabs/grpc,grpc/grpc,yugui/grpc,kskalski/grpc,perumaalgoog/grpc,malexzx/grpc,Crevil/grpc,stanley-cheung/grpc,quizlet/grpc,rjshade/grpc,geffzhang/grpc,murgatroid99/grpc,a-veitch/grpc,jboeuf/grpc,donnadionne/grpc,jcanizales/grpc,firebase/grpc,grani/grpc,makdharma/grpc,fuchsia-mirror/third_party-grpc,zhimingxie/grpc,adelez/grpc,perumaalgoog/grpc,jboeuf/grpc,jtattermusch/grpc,simonkuang/grpc,jcanizales/grpc,ipylypiv/grpc,greasypizza/grpc,zhimingxie/grpc,PeterFaiman/ruby-grpc-minimal,ncteisen/grpc,mehrdada/grpc,perumaalgoog/grpc,andrewpollock/grpc,wcevans/grpc,goldenbull/grpc,leifurhauks/grpc,thunderboltsid/grpc,podsvirov/grpc,matt-kwong/grpc,andrewpollock/grpc,kriswuollett/grpc,thinkerou/grpc,ejona86/grpc,sreecha/grpc,soltanmm-google/grpc,sreecha/grpc,carl-mastrangelo/grpc,miselin/grpc,ipylypiv/grpc,zhimingxie/grpc,vjpai/grpc,dgquintas/grpc,vjpai/grpc,thinkerou/grpc,daniel-j-born/grpc,simonkuang/grpc,quizlet/grpc,soltanmm/grpc,grpc/grpc,makdharma/grpc,adelez/grpc,arkmaxim/grpc,kpayson64/grpc,ppietrasa/grpc,deepaklukose/grpc,kpayson64/grpc,pmarks-net/grpc,dklempner/grpc,deepaklukose/grpc,pmarks-net/grpc,a11r/grpc,pszemus/grpc,hstefan/grpc,7anner/grpc,apolcyn/grpc,sreecha/grpc,pmarks-net/grpc,vjpai/grpc,royalharsh/grpc,ctiller/grpc,kriswuollett/grpc,jtattermusch/grpc,LuminateWireless/grpc,ncteisen/grpc,muxi/grpc,carl-mastrangelo/grpc,leifurhauks/grpc,kriswuollett/grpc,msmania/grpc,ncteisen/grpc,arkmaxim/grpc,adelez/grpc,tengyifei/grpc,vjpai/grpc,yugui/grpc,thinkerou/grpc,ncteisen/grpc,firebase/grpc,dklempner/grpc,VcamX/grpc,geffzhang/grpc,tengyifei/grpc,daniel-j-born/grpc,pszemus/grpc,andrewpollock/grpc,arkmaxim/grpc,malexzx/grpc,yang-g/grpc,matt-kwong/grpc,ppietrasa/grpc,soltanmm-google/grpc,matt-kwong/grpc,murgatroid99/grpc,PeterFaiman/ruby-grpc-minimal,yongni/grpc,rjshade/grpc,msmania/grpc,royalharsh/grpc,thunderboltsid/grpc,donnadionne/grpc,nicolasnoble/grpc,apolcyn/grpc,ipylypiv/grpc,dklempner/grpc,kpayson64/grpc,apolcyn/grpc,podsvirov/grpc,donnadionne/grpc,nicolasnoble/grpc,jcanizales/grpc,dgquintas/grpc,msmania/grpc,infinit/grpc,jtattermusch/grpc,7anner/grpc,carl-mastrangelo/grpc,grani/grpc,ppietrasa/grpc,bogdandrutu/grpc,ipylypiv/grpc,MakMukhi/grpc,stanley-cheung/grpc,fuchsia-mirror/third_party-grpc,sreecha/grpc,podsvirov/grpc,perumaalgoog/grpc,thinkerou/grpc,matt-kwong/grpc,bogdandrutu/grpc,sreecha/grpc,tamihiro/grpc,vjpai/grpc,miselin/grpc,Crevil/grpc,VcamX/grpc,hstefan/grpc,kskalski/grpc,ncteisen/grpc,jboeuf/grpc,soltanmm/grpc,deepaklukose/grpc,fuchsia-mirror/third_party-grpc,MakMukhi/grpc,MakMukhi/grpc,chrisdunelm/grpc,leifurhauks/grpc,malexzx/grpc,pmarks-net/grpc,apolcyn/grpc,geffzhang/grpc,muxi/grpc,kumaralokgithub/grpc,jboeuf/grpc,carl-mastrangelo/grpc,baylabs/grpc,zhimingxie/grpc,MakMukhi/grpc,LuminateWireless/grpc,royalharsh/grpc,pszemus/grpc,matt-kwong/grpc,ejona86/grpc,arkmaxim/grpc,tengyifei/grpc,ananthonline/grpc,quizlet/grpc,thunderboltsid/grpc,grpc/grpc,ipylypiv/grpc,jtattermusch/grpc,jtattermusch/grpc,fuchsia-mirror/third_party-grpc