ci: Add Piglit gl-1.0-blend-func to everyone's skips

I've seen this timing out on Zink, v3d, radeonsi, and Panfrost
periodically, but more and more lately. Try to minimise the damage by
just universally skipping it until someone comes up with a better idea.

Signed-off-by: Daniel Stone <daniels@collabora.com>
Part-of: <!11267>
95 jobs for !11267 with ci-skip-gl-1.0-blend-func in 31 minutes and 50 seconds (queued for 3 seconds)
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