As per the revised documentation for DynamicCallSiteDesc.withArgs:
"NullPointerException - if the argument or its contents are null"

Attached code doesn't throw NPE for argument array containing null:

public class t {
        public static boolean m() throws Throwable {
                DynamicCallSiteDesc desc = DynamicCallSiteDesc.of(ConstantDescs.ofCallsiteBootstrap(
                                                                        ClassDesc.of("BootstrapAndTarget"),
                                                                        "bootstrap2",
                                                                        ClassDesc.of("java.lang.invoke.CallSite")
                                                                        ),
                                                "getTarget",
                                                MethodTypeDesc.ofDescriptor("()I"));

                ConstantDesc[] cd = new ConstantDesc[1];
                cd[0] = null;

                desc.withArgs(cd);

                return true;
        }
        public static void main(String[] args) throws Throwable {
                System.out.println("m: " + m());
        }
}