Load minitest earlier in plugin/extensions specs
Load minitest earlier in plugin/extensions specs

This fixes issues on some older ruby versions, where one of the
libraries needed loads an old version of minitest first.

knut2/sequel,pfarrell/sequel,t-morgan/sequel,pfarrell/sequel,gferguson-gd/sequel,beni55/sequel,uhoh-itsmaciek/sequel,reubano/sequel,t-morgan/sequel,davidbegin/sequel,yazshel/sequel,seeARMS/sequel,reubano/sequel,nju520/sequel,nju520/sequel,gferguson-gd/sequel,davidbegin/sequel,seeARMS/sequel,knut2/sequel,uhoh-itsmaciek/sequel,yazshel/sequel,beni55/sequel