[CALCITE-5423] Implement TIMESTAMP_DIFF function (compatible with Big… #175

Job	Run time
Error Prone (JDK 11)	4m 39s
Error Prone (JDK 11), Guava 31	4m 26s
Linux (JDK 11), Avatica main	8m 6s
CheckerFramework (JDK 11)	9m 56s
CheckerFramework (JDK 11), Guava 29	9m 29s
Druid Tests	7m 1s
Linux (JDK 11), Pacific/Chatham Timezone	8m 48s
Linux (JDK 17)	8m 14s
Linux (JDK 18)	7m 45s
Linux (JDK 8), Oldest Guava, America/New_York Timezone	8m 33s
Linux (JDK 8) Slow Tests	0s
macOS (JDK 18)	18m 44s
Windows (JDK 17)	12m 15s
Windows (JDK 8)	14m 13s
	2h 2m 9s

Provide feedback