Testing runnerv2service without command.SetEnvDumpCommandForTesting results in fork bomp

[adambabik]

Running runnerv2service tests without the following fragment:

func init() {
	command.SetEnvDumpCommandForTesting()
}

results in fork bomb.

The goal of this issue is to understand exactly what happens and try to write a more bullet proof code so that forgetting this call in init() does not destroy the local environment.

This problem was discovered in #727.