tests: Get a file through an absolute symlink within a subdirectory

tests: Get a file through an absolute symlink within a subdirectory

This shows that read_symlink_reparse() is broken when trying to
replace an absolute with a relative filename within a
share.

read_symlink_reparse() is used only in openat_pathref_fsp_nosymlink()
so far to chase symlinks for non-lcomp path components. Chasing lcomp
symlinks is done through non_widelink_open(), which gets it right.

Bug: https://bugzilla.samba.org/show_bug.cgi?id=15505

Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>