Tomcat switch should be disabled by default

[noullet]

I had the very bad surprise to find an undocumented Tomcat kill switch port:

grails-standalone/src/runtime/grails/plugin/standalone/Launcher.java

Line 151 in 9e2e902

startKillSwitchThread(port);

This idea appears to come from the Tomcat plugin, which is fine for development but I fail to see any benefit outside of a development environment. Even if there is a valid use case, such feature should be clearly documented and opt-in in a potential "production" package, here it's not even opt-out and I don't see any mention of it anywhere.

Sorry if I sound a bit bitter, don't be mistaken I am very grateful for your work and amazing open source contributions but finding such a big longstanding security hole that could have been easily avoided (e.g. by simply not adding this feature) is quite frustrating.