Adding unit test for ephemeral feature flag

This was something that was missing in #707.
Adding a new test to make sure the ephemeral feature flag from upstream
is set up correctly by the script.

test/entrypoint/should_retry_configuring/config.sh

@@ -20,6 +20,7 @@ error(){
   exit 1
 }
 
+echo "$*" > runner_config
 success "I'm pretending the configuration is not successful"
 # increasing a counter to measure how many times we restarted
 count=`cat counter 2>/dev/null|| echo "0"`