`SimulationMacroCache` over-applies caching

[anth-volk]

I believe that when merging the changes that created SimulationMacroCache (https://github.com/PolicyEngine/policyengine-core/pull/224), we introduced a subtle change in logic that now applies caching too liberally.

Prior to the change, there was a function within Simulation called _get_macro_cache that did two things: determine if caching should be applied when calculating a variable and provide the cache path where necessary. The first check this method did is available at the line below: https://github.com/PolicyEngine/policyengine-core/blob/62e6be0d918f32e8bad85d85181223f2f50bad7e/policyengine_core/simulations/simulation.py#L1407 Basically, if a dataset was not provided, no caching was utilized; otherwise, all other checks occurred.

SimulationMacroCache broke _get_macro_cache into two different methods, and the new check_macro_cache method does a couple of checks around datasets, before this line: https://github.com/PolicyEngine/policyengine-core/blob/96a467aeb917f9771fd5ec28b227b1b61749f9ad/policyengine_core/simulations/simulation.py#L1435 So that if a dataset is provided, caching is definitely utilized, otherwise, all other checks occur.

This means that all Microsimulation runs provide caching on all variables, and theoretically, some Simulation runs without datasets (e.g., household calculator) might also cache; this is as opposed to select variables being cached only when Microsimulation runs provide an exhaustive_parameter_deps value, as I believe was the method before.