[flytepropeller] Add Tests in v1alpha.go including `array_test.go`, … #987

Job	Run time
test-bootstrap	24s
build-and-push-single-binary-image	6m 5s
build-and-push-sandbox-bundled-image	3m 10s
sandbox-bundled-functional-tests	9m 31s
	19m 10s

Provide feedback