early start zygote_secondary as well

- late start of zygote_secondary leads into occasional
  1 second wait for starting system service.
- Early start secondary zygote so that there is no additional
  wait.

bug: 37508384
Test: python packages/services/Car/tools/bootanalyze/bootanalyze.py -r -c packages/services/Car/tools/bootanalyze/config.yaml -n 100 -f -e 16 -w 30
Change-Id: I2e4eb0b59a9a8417b56a72fe2de6fa2a6e1ab0a2