tests/test-double-merge

test-merge-tools: windows fixes

- /bin/cat does not exist, expect 'cat'
- non-interactive mode is not correctly detected in pysh, force it

#!/bin/sh

hg init repo
cd repo

echo line 1 > foo
hg ci -qAm 'add foo' -d "1000000 0"

# copy foo to bar and change both files
hg cp foo bar
echo line 2-1 >> foo
echo line 2-2 >> bar
hg ci -m 'cp foo bar; change both' -d "1000000 0"

# in another branch, change foo in a way that doesn't conflict with
# the other changes
hg up -qC 0
echo line 0 > foo
hg cat foo >> foo
hg ci -m 'change foo' -d "1000000 0"

# we get conflicts that shouldn't be there
hg merge -S
hg merge --debug

echo "-- foo --"
cat foo

echo "-- bar --"
cat bar