[CALCITE-6665] Add isEmpty metadata to check if a relational expressi… #14347

Job	Run time
Windows (JDK 21)	0s
Linux (JDK 8, oldest Guava, America/New_York Timezone)	0s
Windows (JDK 17)	0s
Windows (JDK 8)	0s
Linux (JDK 8, latest Guava, America/New_York Timezone)	0s
Linux (JDK 11, Pacific/Chatham Timezone)	0s
Linux (JDK 17)	0s
Linux (JDK 11, Avatica main)	0s
CheckerFramework (JDK 11)	11m 0s
Linux (JDK 21)	0s
Linux (JDK 23)	0s
macOS (JDK 21)	0s
ErrorProne (JDK 11, latest Guava)	0s
CheckerFramework (JDK 11, oldest Guava)	10m 41s
Druid Tests	0s
Linux (JDK 8) Slow Tests	0s
	21m 41s

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