java-opts.sh should not set Xmx option for JAVA_MAX_MEM_RATIO configuration

Current [java-opts.sh](https://github.com/infinispan/infinispan-images/blob/main/modules/org/infinispan/distribution/jvm/added/bin/java-opts.sh) script sets Xmx and prevent [openjdk machinery](https://developers.redhat.com/articles/2023/03/07/overhauling-memory-tuning-openjdk-containers-updates#what_to_expect_in_the_next_container_update) to do proper settings.