clean up coverage files in test directory too [skip ci]
clean up coverage files in test directory too [skip ci]

tangrams/variant,edwiincao/variant,daniel-j-h/variant,tempbottle/variant,tangrams/variant,daniel-j-h/variant,edwiincao/variant,tempbottle/variant,edwiincao/variant,daniel-j-h/variant,tempbottle/variant,tangrams/variant