[CALCITE-6666] Support Oracle SYSDATE and SYSTIMESTAMP functions #14029

Job	Run time
CheckerFramework (JDK 11)	10m 51s
Linux (JDK 11, Avatica main)	14m 31s
CheckerFramework (JDK 11, oldest Guava)	10m 58s
ErrorProne (JDK 11, latest Guava)	4m 21s
Druid Tests	6m 59s
Linux (JDK 11, Pacific/Chatham Timezone)	10m 43s
Linux (JDK 21)	10m 26s
Linux (JDK 17)	10m 27s
Linux (JDK 23)	12m 27s
Linux (JDK 8, latest Guava, America/New_York Timezone)	12m 13s
Linux (JDK 8, oldest Guava, America/New_York Timezone)	10m 55s
Linux (JDK 8) Slow Tests	0s
macOS (JDK 21)	44m 41s
Windows (JDK 17)	15m 28s
Windows (JDK 21)	15m 22s
Windows (JDK 8)	15m 58s
	3h 26m 20s

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