[WIN32K:NTUSER] Get rid of the cached window station Name member, and instead just use the name stored in the NT Object's header.
CORE-11933 and PR #621.
- Remove the related hack-FIXMEs;
- Adjust NtUserGetObjectInformation() in accordance.
- Retrieve the window-station/desktop object type string in NtUserGetObjectInformation()
also from the NT Object's header.
Also simplify the UOI_FLAGS case of NtUserGetObjectInformation() by reading
the handle inheritance information directly from the OBJECT_HANDLE_INFORMATION
structure returned by ObReferenceObjectByHandle().