pkg/bisect: increase number of tries to 8
pkg/bisect: increase number of tries to 8

With 5 tries sometimes only 1 fails,
and sometimes we probably have false negatives.
Increase number of tries to 8 and compress
results if they all are the same.

Update #501

xairy/syzkaller,xairy/syzkaller,xairy/syzkaller,xairy/syzkaller,google/syzkaller,xairy/syzkaller,google/syzkaller,google/syzkaller,google/syzkaller,google/syzkaller,xairy/syzkaller,xairy/syzkaller,google/syzkaller,google/syzkaller