simplify "test" target in makefile

[glensc]

makes make test to fail with exit 1 when tests can't be ran
refs 1807673

[krakjoe]

Since the test rule has already been similarly simplified, and since changing the exit status may break CI for anyone who has a CI configuration where CLI is not built in some configuration, but is using the same .travis/appveyor YAML for a configuration that does, and since nothing actually failed if you didn't build CLI, I'm closing this PR.