resize! from #315

[kanav99]

Credits @devmotion. I just took the resize implementation from #315 as I explained in #325 (comment)

[devmotion]

As I mentioned in #325 (comment), I think we should reconsider the order in which we want to add changes. The PR from which the resize! implementation is taken is outdated and should be closed. So IMO it feels wrong to add changes from that PR.

[kanav99]

Even though the PR was closed, I dont think considering this resize is bad, its more extendible more clean.

[devmotion]

I agree that it's better than the current version but I don't see in what way it would be better than the changes in #325? On the contrary, I think the changes in #325 are superior since resize!(::NLSolver, ::Int) does not consider any special cases for NLAnderson anymore. Since hopefully the registry will be updated soon with the correctly upper bounded DiffEqBase dependencies for OrdinaryDiffEq and StochasticDiffEq, I think the main goal should be to agree on a final version of #325.

IMO, by merging this PR we do not gain much at the moment, it seems it would mostly be helpful for SciML/OrdinaryDiffEq.jl#878. I'm pretty sure we would have to rebase #325, which provides similar but slightly improved resize changes.

[ChrisRackauckas]

Looks like we are going straight to the newer nlsolvers.