Add GPU tests

With NLPModels 0.21, we try to support the NLPModel API for CuArray types.

For instance, things like that are being done: https://github.com/JuliaSmoothOptimizers/NLPModelsTest.jl/blob/3409ae7a292a1e7baa5955787c2db56aa42e386f/test/runtests.jl#L76

I am suspecting most of this package is compatible already, but maybe not 100%, e.g. https://github.com/JuliaSmoothOptimizers/QuadraticModels.jl/blob/main/src/qps.jl

Start with the referenced test/runtests.jl coverage in NLPModelsTest.jl and inspect src/qps.jl for CuArray handling. Compare the existing API tests with GPU-compatible cases, then run the package tests with CuArray support; done means the relevant NLPModel API behavior is covered and passes for GPU arrays.

Written by the indexing model from the issue text.