Merge more stores/loads

[xtqqczze]

I don't think it's a good motivation to add more. I think these copies could be optimized by jit if we revive #95823

Originally posted by @EgorBo in #105208 (comment)

[dotnet-policy-service]

Tagging subscribers to this area: @JulieLeeMSFT, @jakobbotsch
See info in area-owners.md if you want to be subscribed.