opa test: change exit status when tests are skipped (#3774)
opa test: change exit status when tests are skipped (#3774)

When `-z` is passed to `opa test`, skipped tests will not affect
the exit code. (When not passed, skipped tests produce the same
exit code as failed tests.)

Fixes #3773.

Signed-off-by: Kirk Patton <a68fc2d78a11989f589854b54283df8feb02a341@verizonmedia.com>
open-policy-agent/opa,tsandall/opa,tsandall/opa,open-policy-agent/opa,open-policy-agent/opa,tsandall/opa,open-policy-agent/opa,tsandall/opa,open-policy-agent/opa,tsandall/opa,open-policy-agent/opa,tsandall/opa