[CALCITE-5865] ClassCastException with FLOOR and CEIL on conformances… #230

Job	Run time
Linux (JDK 8), Oldest Guava, America/New_York Timezone	12m 57s
Windows (JDK 17)	19m 36s
Windows (JDK 8)	21m 6s
Linux (JDK 11), Pacific/Chatham Timezone	12m 51s
Linux (JDK 17)	12m 35s
Linux (JDK 8), Latest Guava, America/New_York Timezone	14m 8s
Error Prone (JDK 11), Guava 31	5m 23s
Linux (JDK 11), Avatica main	1h 50m 5s
CheckerFramework (JDK 11)	15m 55s
CheckerFramework (JDK 11), Guava 29	12m 54s
Linux (JDK 19)	12m 33s
Druid Tests	9m 33s
Linux (JDK 8) Slow Tests	32m 16s
macOS (JDK 19)	30m 4s
	5h 21m 56s

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