Ben Edgington 8620adcdf1 Correct the duration of HISTORICAL_ROOTS_LIMIT
The duration of HISTORICAL_ROOTS_LIMIT is:
    SECONDS_PER_SLOT * SLOTS_PER_HISTORICAL_ROOT * HISTORICAL_ROOTS_LIMIT
which is
    12s * 2^13 * 2^24 = 1.65e12s = 52,262 years
2020-02-14 14:29:45 +00:00
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