Fix check_macro_cache logic around self.is_over_dataset

[anth-volk]

Fixes #268. This reverts the logic within Simulation.check_macro_cache to ensure that when it checks the value of self.is_over_dataset, it follows the same logic present prior to the integration of SimulationMacroCache, i.e., the logic available at

policyengine-core/policyengine_core/simulations/simulation.py

Line 1407 in 62e6be0

if not self.is_over_dataset:

.

This does not add tests. While SimulationMacroCache did when it was merged, it was unclear how it actually fit into Simulation itself. Moving forward, we should clarify the aims and requirements of the macro cache, refactor Simulation (open as #264), then add tests to Simulation itself to prevent a similar issue