Sanitize JvmArgs

[The-File]

Apparently some threerings products are using jvm arguments that are not valid in more recent java versions.

One notorious instance being the "-XX:+AggressiveOpts" arguments used by getdown to launch Spiral Knights with. This throws an error for recent versions of the JVM.

As per official citation of its removal - https://bugs.openjdk.org/browse/JDK-8150552

[bekoenig]

Hi,
we have the same issue with other JVM arguments. A simple solution was to set "-XX:+IgnoreUnrecognizedVMOptions" in the getdown.txr.
I think this is a good default to avoid problems on further JVM upgrades.
Greetings,
Ben

[The-File]

Thanks ben, I'll check with deploying the "-XX:+IgnoreUnrecognizedVMOptions" runtime argument in an extra.txt file rather than modifying the getdown.jar to mangle interpreting the getdown.txt itself to avoid "-XX:+AggressiveOpts"