bump diego-stress-tests
bump diego-stress-tests

Submodule src/code.cloudfoundry.org/diego-stress-tests b8d5632..0fc8578:
  > Always cleanup cfhomes and wait for all subprocesses to finish
  > few improvements to the cf cli
  > replace os.Exit with panic to give a chance for defers to run
  > Cancel the context properly in case of errors

Signed-off-by: Nima Kaviani <0ebde517669f70c2aec92dc89d4950413b825ec0@us.ibm.com>

cloudfoundry-incubator/diego-perf-release,cloudfoundry-incubator/diego-perf-release