There is a simple test bug in Leyden:

$ CONF=macosx-aarch64-server-fastdebug make images test TEST=tools/sincechecker/modules/java.base/JavaBaseCheckSince.java

src/java.base/java/lang/System.java:1526 method: boolean java.lang.System.AOTIsTraining(): `@since` version: 9; should be: 25
src/java.base/java/lang/System.java:1531 method: void java.lang.System.AOTEndTraining(): `@since` version: 9; should be: 25
java.lang.Exception: The `@since` checker found 2 problems
at SinceChecker.checkModule(SinceChecker.java:284)
at SinceChecker.main(SinceChecker.java:145)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
at java.base/java.lang.reflect.Method.invoke(Method.java:565)
at com.sun.javatest.regtest.agent.MainActionHelper$AgentVMRunnable.run(MainActionHelper.java:333)
at java.base/java.lang.Thread.run(Thread.java:1447)