IPM exec when locations have more than 1 billion individuals

[JavadocMD]

When locations contain more than 1 billion individuals, IPM calculation breaks down with an error like:

File ~/Workspaces/epymorph2/epymorph/simulator/basic/ipm_exec.py:385, in IpmExecutor._distribute(self, cohorts, events)
    [383] else:
    [384]     # event is coming from a modeled compartment
--> [385]     selected = self._rng.multivariate_hypergeometric(
    [386]         cohorts[:, cidx], occur
    [387]     ).astype(SimDType)
    [388]     occurrences[:, eidx] = selected

File numpy/random/_generator.pyx:4252, in numpy.random._generator.Generator.multivariate_hypergeometric()

ValueError: When method is "marginals", sum(colors) must be less than 1000000000.

Need to figure out a more graceful way to handle this. (One option might be a check to switch to method="count", but that's really slow.)