tests: config::stress: free `git_config` structs
tests: config::stress: free `git_config` structs

saurabhsuniljain/libgit2,magnus98/TEST,leoyanggit/libgit2,joshtriplett/libgit2,Corillian/libgit2,stewid/libgit2,KTXSoftware/libgit2,leoyanggit/libgit2,joshtriplett/libgit2,jeffhostetler/public_libgit2,magnus98/TEST,jeffhostetler/public_libgit2,Corillian/libgit2,yongthecoder/libgit2,magnus98/TEST,KTXSoftware/libgit2,jeffhostetler/public_libgit2,stewid/libgit2,yongthecoder/libgit2,jeffhostetler/public_libgit2,KTXSoftware/libgit2,Tousiph/Demo1,jeffhostetler/public_libgit2,stewid/libgit2,saurabhsuniljain/libgit2,saurabhsuniljain/libgit2,Corillian/libgit2,yongthecoder/libgit2,Corillian/libgit2,saurabhsuniljain/libgit2,yongthecoder/libgit2,Tousiph/Demo1,leoyanggit/libgit2,jeffhostetler/public_libgit2,joshtriplett/libgit2,magnus98/TEST,Tousiph/Demo1,leoyanggit/libgit2,saurabhsuniljain/libgit2,Tousiph/Demo1,yongthecoder/libgit2,joshtriplett/libgit2,KTXSoftware/libgit2,joshtriplett/libgit2,joshtriplett/libgit2,stewid/libgit2,magnus98/TEST,KTXSoftware/libgit2,magnus98/TEST,KTXSoftware/libgit2,Corillian/libgit2,leoyanggit/libgit2,Tousiph/Demo1,stewid/libgit2,stewid/libgit2,Tousiph/Demo1,yongthecoder/libgit2,Corillian/libgit2,leoyanggit/libgit2,saurabhsuniljain/libgit2