[PATCH 1/2] ntdll: Unify get_file_info and fd_get_file_info.

[Erich E. Hoover]

get_file_info and fd_get_file_info duplicate the same logic except
that they either work on paths or file descriptors (respectively).
This patch consolidates these two routines and moves some of the
path-specific behavior to an updated [fd_]is_mount_point.  Besides
consolidation, this patch simplifies the reparse point patches (coming
soon!) since there's now only one routine that handles both path-based
and fd-based requests for file information.

Best,
Erich