Delete examples/GSets_timing.jl

[lgoettgens]

this contains some benchmarks from two years ago, that have not been used since then (at least I think so).

Towards #280.

[HereAround]

I actually touched on this with @mjrodgers a while ago; no strong opinion if I recall correctly, but rather for @fingolfin to decide.

[mjrodgers]

I created them at the request of @fingolfin so that we could compare timings of the GSet methods among different versions and check for regressions. At the moment we don't have any automated timing tests, but if a user is modifying GSet code they can run these benchmarks against their commit to see if the timings are affected.

Is the point that the examples folder needs to go away? If so, maybe there is another place for these to be moved to. As is, they don't add anything to CI or take up much memory, so I don't know the motivation to delete them.