BUG: Fix out of order emission of performance with minutely data.

With the benchmark returns marked at midnight, the performance packet
for a day was emitted *before* any events for that day were processed.

Fix by expecting benchmarks marked at the market close, for backtests
that use minute data but emit performance results daily, so that the
benchmark handles at the end of day.

TST: Also, add test that exercises the event loop with minutely data,
(with benchmarks that are marked end of day), since that combination
was previously uncovered.