Namespace shares the same name between Jenkins Performance test jobs

In common_job_properties.groovy is defined getKubernetesNamespace(def testName) which runs only after seed job.

Expected behaviour is to create a new namespace with every test run.

The failure was observed after retrying JdbcIOIT job. The first failure did not deleted namespace. Next jobs failed because of:

+ kubectl --kubeconfig=/home/jenkins/jenkins-slave/workspace/beam_PerformanceTests_JDBC/config-jdbcioit-1526904136153 create namespace jdbcioit-1526904136153 Error from server (AlreadyExists): namespaces "jdbcioit-1526904136153" already exists

Here are examples of jobs on Jenkins:
https://builds.apache.org/view/A-D/view/Beam/job/beam_PerformanceTests_JDBC/601/console
and
https://builds.apache.org/view/A-D/view/Beam/job/beam_PerformanceTests_JDBC/602/console