Add support for initializing ordered_set with an initializer_list
Add support for initializing ordered_set with an initializer_list

mbudiu-vmw/p4c-clone,p4lang/p4c,mbudiu-vmw/p4c-clone,p4lang/p4c,hanw/p4c,mbudiu-vmw/p4c-clone,p4lang/p4c,hanw/p4c,hanw/p4c,p4lang/p4c,hanw/p4c,mbudiu-vmw/p4c-clone,p4lang/p4c