kiji-scoring-server: SCORSRVR-24. Remove nondeterminism from tests which use TestUtils.scan

issue: https://jira.kiji.org/browse/SCORSRVR-24
review: https://review.kiji.org/r/1869
commit: https://github.com/kijiproject/kiji-scoring-server/commit/5eb68df40dab2a3239c2bfa9543ed901adf112d6