Run tests in parallel if possible
Run tests in parallel if possible

When running tests for a specific package,
run them in parallel if they are not marked as
a "serial package"

[#149898305]

Signed-off-by: Dennis Leon <84f467a5e250ceeacb4292b28bf3ac3f822ea696@pivotal.io>

cloudfoundry-incubator/cf-networking-release,cloudfoundry-incubator/cf-networking-release,cloudfoundry-incubator/cf-networking-release,cloudfoundry-incubator/cf-networking-release