tests/test-race

performance: do not stat() things when not required

Ignore unknown files if we don't need them (eg in hg diff).
It slows things down a little bit for big trees (kernel repo), since _join()
is called for each file instead of for each directory.

fix issue567

#!/bin/sh

mkdir t
cd t
hg init
echo a > a
hg add a
hg commit -m test

# do we ever miss a sub-second change?
for i in 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20; do
    hg co -qC 0
    echo b > a
    hg st
done