Replace deprecated asList method with asInstanceOf #1707

Job	Run time
scan	2m 4s
database-tests (ORACLE)	4m 28s
database-tests (DB2)	7m 7s
build	36m 15s
Build and Publish Images / Build extra images	26s
Build and Publish Images / Prepare Job	13s
Build and Publish Images / Publish (spring-cloud-dataflow-tasklauncher-sink-rabbit, spring-cloud-dataflow-tasklauncher/sprin...	1m 41s
Build and Publish Images / Publish (spring-cloud-dataflow-single-step-batch-job, spring-cloud-dataflow-single-step-batch-job...	1m 17s
Build and Publish Images / Publish (spring-cloud-dataflow-server, spring-cloud-dataflow-server/target, springcloud/spring-cl...	1m 27s
Build and Publish Images / Publish (spring-cloud-dataflow-composed-task-runner, spring-cloud-dataflow-composed-task-runner/t...	1m 34s
Build and Publish Images / Publish (spring-cloud-dataflow-tasklauncher-sink-kafka, spring-cloud-dataflow-tasklauncher/spring...	1m 47s
Build and Publish Images / Publish (spring-cloud-skipper-server, spring-cloud-skipper/spring-cloud-skipper-server/target, sp...	1m 46s
done	1s
	1h 0m 6s

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