Fix debugger tests - sdk issue (#2503)

Summary:
For sdk < 17.4 there is no profiling support and we were returning `nil` from `ETCoreMLModelAnalyzer` if the profiler was nil. We could still support model debugging even if we can't profile the model, the change addresses it by creating the `ETCoreMLModelAnalyzer` instance.

Pull Request resolved: https://github.com/pytorch/executorch/pull/2503

Reviewed By: shoumikhin

Differential Revision: D55076647

Pulled By: tarun292

fbshipit-source-id: 28f96042e5f89aef7bd6ffc8ada52191594c69f2