Figure out how to nicely shut down the server on fail

[WalshyDev]

Right now we System.exit(1) which doesn't exit very cleanly and the server implementation freaks out.

e2e-tester/src/main/java/io/github/slimefun/e2etester/framework/TestFramework.java

Line 93 in dae0746

System.exit(1);

Is there a native way to do this within Bukkit? If not, is there a better way?