[SQL] Fix missing postAggregations for Timeseries and TopN

[jihoonson]

In SQL, postAggregations such as SUM(m1) + SUM(m2) are missing in the query plan, thereby resulting in nulls. See the newly added unit tests in the patch for example queries.

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This change is 

[clintropolis]

👍

[gianm]

@jihoonson the failure looks legit… probably related to "second" query granularity being too much for the test box to handle?

testPostAggWithTimeseries(io.druid.sql.calcite.CalciteQueryTest)  Time elapsed: 88.982 sec  <<< ERROR!
java.lang.OutOfMemoryError: GC overhead limit exceeded
	at io.druid.java.util.common.granularity.PeriodGranularity.increment(PeriodGranularity.java:115)
	at io.druid.java.util.common.granularity.Granularity$IntervalIterator.next(Granularity.java:235)
	at io.druid.java.util.common.granularity.Granularity$IntervalIterator.next(Granularity.java:205)
	at com.google.common.collect.ImmutableCollection$Builder.addAll(ImmutableCollection.java:301)
	at com.google.common.collect.ImmutableList$Builder.addAll(ImmutableList.java:691)
	at com.google.common.collect.ImmutableList.copyOf(ImmutableList.java:275)
	at com.google.common.collect.ImmutableList.copyOf(ImmutableList.java:226)
	at io.druid.segment.QueryableIndexStorageAdapter$CursorSequenceBuilder.build(QueryableIndexStorageAdapter.java:381)
	at io.druid.segment.QueryableIndexStorageAdapter.makeCursors(QueryableIndexStorageAdapter.java:313)
	at io.druid.query.QueryRunnerHelper.makeCursorBasedQuery(QueryRunnerHelper.java:59)
	at io.druid.query.timeseries.TimeseriesQueryEngine.process(TimeseriesQueryEngine.java:50)
	at io.druid.query.timeseries.TimeseriesQueryRunnerFactory$TimeseriesQueryRunner.run(TimeseriesQueryRunnerFactory.java:104)

[jihoonson]

@gianm thanks. I've fixed the test.

[gianm]

thanks @jihoonson!

[gianm]

I believe this fixes a bug introduced by #5788, so it must be included in 0.12.3. I'll mark it.