executor: adopt for new kcov
executor: adopt for new kcov

Now kcov exposes only uintptr-sized PCs.

lorenzo-stoakes/syzkaller,sploving/syzkaller,zoulasc/syzkaller,sploving/syzkaller,xairy/syzkaller,dotweiba/syzkaller,hyz0906/syzkaller,xairy/syzkaller,lorenzo-stoakes/syzkaller,google/syzkaller,zoulasc/syzkaller,xairy/syzkaller,sploving/syzkaller,google/syzkaller,google/syzkaller,dotweiba/syzkaller,xairy/syzkaller,xairy/syzkaller,hyz0906/syzkaller,xairy/syzkaller,google/syzkaller,lorenzo-stoakes/syzkaller,zoulasc/syzkaller,google/syzkaller,dotweiba/syzkaller,zoulasc/syzkaller,hyz0906/syzkaller,hyz0906/syzkaller,dotweiba/syzkaller,sploving/syzkaller,google/syzkaller,google/syzkaller,hyz0906/syzkaller,xairy/syzkaller