[PATCH v2 0/2] MR10661: Draft: scrrun: Implement folder stubs

[Francis De Brabandere (＠francisdb)]

Return a new IFolder for the parent directory of This->path, reusing
the existing get_parent_folder_name() helper. Return a NULL IFolder
(Nothing in VBScript) for root paths.

This fixes VBScript expressions such as `folder.ParentFolder & "\sub"`
that previously failed with error 445 ("Object doesn't support this
action") because the getter was a stub returning E_NOTIMPL.

--
  v2: scrrun: Implement IFolder::get_ParentFolder.
      scrrun: Fix BSTR length off-by-one in create_folder.
 
https://gitlab.winehq.org/wine/wine/-/merge_requests/10661