tests/test-issue1089

shrink-revlog: improve performance: use changegroup instead of revisions

Before:
real	0m23.971s

Now:
real	0m4.229s

The only case where the output would be different is if the newer hg was using
a different diff algorithm than used originally.

#!/bin/sh

hg init a
cd a
mkdir a
echo a > a/b
hg ci -Am m
hg rm a
hg ci -m m a

mkdir a b
echo a > a/b
hg ci -Am m
hg rm a
cd b
# relative delete
hg ci -m m ../a