bisect: use array.array rather than lists for ancestor lists
This nearly doubles performance and cuts memory usage in half on large
bisections.
#!/bin/sh
"$TESTDIR/hghave" execbit || exit 80
hg init
echo a > a
hg ci -d'0 0' -Am'not executable'
chmod +x a
hg ci -d'1 0' -m'executable'
hg id
hg up 0
hg id
test -x a && echo executable -- eek || echo not executable -- whew