Fuzz: use-of-uninitialized in unsqueeze
Fuzz: use-of-uninitialized in unsqueeze

Previous shortcut logic created uninitialized images even for non-empty channels
libjxl/libjxl,libjxl/libjxl,libjxl/libjxl,libjxl/libjxl,libjxl/libjxl,libjxl/libjxl,libjxl/libjxl,libjxl/libjxl