fix, speed up and clean up child tests
fix, speed up and clean up child tests

Small issue with subshells sending text to STDERR about the signal
received, breaking the text check (result of sending signals to process
group). Changed them to only check STDOUT, where the test text is sent.

Previously used a sleep time of 500 milliseconds when 50 worked fine.
This sped up the child tests a lot.

Everything else are cleaning up lots of useless checks, hardcoded times,
and replace subshell test calls use of bash with standard /bin/sh.

hashicorp/consul-template,hashicorp/consul-template