The security manager will be deprecated for removal in JDK 17 as part of JEP 411, JDK-8264713. Once this JEP is integrated, the JavaFX tests that set a security manager using System.setSecurityManager will fail when run using JDK 17 unless run with "java -Djava.security.manager=allow".
We will build JavaFX using JDK 16 until after JDK 17 ships (so we won't switch until JavaFX 18), but we need todo this for JavaFX 17 so we can test builds of JavaFX 17 using JDK 17 without having several of the tests fail.