[CALCITE-6474] Aggregate with constant key can get a RowCount greater… #261

Job	Run time
Windows (JDK 8)	15m 49s
Windows (JDK 17)	14m 50s
Windows (JDK 21)	16m 51s
Linux (JDK 8), oldest Guava, America/New_York Timezone	10m 56s
Linux (JDK 11), Avatica main	12m 8s
Linux (JDK 11), Pacific/Chatham Timezone	11m 37s
Linux (JDK 21)	12m 10s
Linux (JDK 17)	10m 32s
Linux (JDK 22)	10m 3s
Linux (JDK 8), latest Guava, America/New_York Timezone	12m 4s
Error Prone (JDK 11), latest Guava	6m 28s
CheckerFramework (JDK 11)	12m 35s
Druid Tests	9m 13s
CheckerFramework (JDK 11), oldest Guava	12m 51s
Linux (JDK 8) Slow Tests	6m 43s
macOS (JDK 21)	42m 54s
	3h 37m 44s

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