tests/test-filelog.py.out

copyfile: add an optional parameter to copy other stat data

Contrary to the comment, I didn't see any evidence that we were copying
atime/mtime at all. This adds a parameter to copyfile to optionally copy it and
other stat data, with the default being to not copy it.

Many systems don't support changing the timestamp of a symlink, but we don't
need that in general anyway -- copystat is mostly useful for editors, most of
which will dereference symlinks anyway.

ERROR: FIXME: This is a known failure of filelog.size for data starting with \1\n
OK.