Bug#1081275: gtk4: gdk/memorytexture test failing in r16g16b16-float/ngl on mips64el only

[Alessandro Astone]

I'm also seeing this on my local x86_64 machine when running:

VK_DRIVER_FILES=/usr/share/vulkan/icd.d/lvp_icd.x86_64.json 
LIBGL_ALWAYS_SOFTWARE=1 GALLIUM_DRIVER=softpipe 
/usr/libexec/installed-tests/gtk-4.0/gdk/memorytexture

Both the ngl and the vulkan r16g16b16-float tests often fail on softpipe 
and lavapipe respectively. llvmpipe seems unaffected instead.