[PATCH v2 0/3] MR7653: windowscodecs/metadata: Always initialize handler pointer.

[Nikolay Sivov (＠nsivov)]

In case of empty block reader we currently return uninitialized pointer
that is accessed later.

Signed-off-by: Nikolay Sivov <nsivov(a)codeweavers.com>

--
  v2: windowscodecs/tests: Add some tests for the App0 reader.
 
https://gitlab.winehq.org/wine/wine/-/merge_requests/7653