merge: pass wctx to batchremove and batchget
We would like to migrate direct calls of repo.wvfs/wwrite/wread/etc to a
call on the relevant workingfilectx, both as a cleanup (to reduce the number of
working copy functions on `repo`), and also to facilitate an in-memory merge
that doesn't write to the working copy.
In order to do that, the first step is to ensure we pass the target wctx around
and perform our writes and reads on it. Later, this object might become a
memctx.
$ hg init
$ echo 123 > a
$ hg add a
$ hg commit -m "first" a
$ mkdir sub
$ echo 321 > sub/b
$ hg add sub/b
$ hg commit -m "second" sub/b
$ cat sub/b
321
$ hg co 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ cat sub/b 2>/dev/null || echo "sub/b not present"
sub/b not present
$ test -d sub || echo "sub not present"
sub not present