[CALCITE-4918] Add a VARIANT data type #13479

Job	Run time
Windows (JDK 17)	16m 55s
Windows (JDK 17)	16m 55s
Windows (JDK 8)	1m 43s
Windows (JDK 8)	18m 6s
Linux (JDK 21)	10m 7s
Linux (JDK 21)	10m 7s
Linux (JDK 17)	5m 57s
Linux (JDK 17)	10m 42s
Linux (JDK 11), Pacific/Chatham Timezone	10m 48s
Linux (JDK 11), Pacific/Chatham Timezone	10m 48s
Linux (JDK 8), latest Guava, America/New_York Timezone	12m 8s
Linux (JDK 8), latest Guava, America/New_York Timezone	12m 8s
Linux (JDK 8), oldest Guava, America/New_York Timezone	10m 33s
Linux (JDK 8), oldest Guava, America/New_York Timezone	10m 33s
Windows (JDK 21)	1m 52s
Windows (JDK 21)	15m 28s
Error Prone (JDK 11), latest Guava	5m 38s
Error Prone (JDK 11), latest Guava	2m 44s
Linux (JDK 11), Avatica main	14m 21s
Linux (JDK 11), Avatica main	14m 21s
CheckerFramework (JDK 11)	12m 47s
CheckerFramework (JDK 11)	11m 17s
CheckerFramework (JDK 11), oldest Guava	12m 34s
CheckerFramework (JDK 11), oldest Guava	10m 24s
Linux (JDK 22)	12m 9s
Linux (JDK 22)	12m 9s
macOS (JDK 21)	45m 12s
macOS (JDK 21)	45m 12s
Druid Tests	9m 9s
Druid Tests	9m 9s
Linux (JDK 8) Slow Tests	0s
Linux (JDK 8) Slow Tests	0s
	6h 31m 56s

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