tests/test-1102

store: simplify walking

- fold in main walking function
- eliminate recursion (especially recursive yielding!)
- eliminate default args

#!/bin/sh

rm -rf a
hg init a
cd a
echo a > a
hg ci -Am0
hg tag t1 # 1
hg tag --remove t1 # 2

hg co 1
hg tag -r0 t1
hg tags