Allow testsuite/scripts to deal with -Dts.ee9

Th addition of testsuite/scripts breaks WildFly Preview testing.

https://ci.wildfly.org/viewLog.html?buildId=245524&buildTypeId=WF_Ee9BootableJarLinuxJdk8&tab=buildLog&_focus=4790

That's a bootable jar test job. I wouldn't be surprised if the non-bootable jar fails as well.