Added new scan executor metric #14606

Job	Run time
fastbuild	1m 55s
mvn (qa-checks, 17, verify javadoc:jar -Psec-bugs -DskipTests -Dspotbugs.timeout=3600000)	8m 32s
mvn (errorprone, 17, verify -Derrorprone -PskipQA)	2m 52s
mvn (unit-tests, 17, verify -PskipQA -DskipTests=false)	8m 8s
mvn (compat, 17, package -DskipTests -Dversion.hadoop=3.0.3 -Dversion.zookeeper=3.5.10)	1m 24s
	22m 51s

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