[JDK-8361426] JDK26+ incompatibility because of jdk.internal.ref.Cleaner removal.

[farquet]

The jdk.internal.ref.Cleaner class has now been removed from OpenJDK mainline (JDK26+).

However, Chronicle-Map is using this internal class explicitly here:

Chronicle-Map/src/main/java/net/openhft/chronicle/hash/impl/util/CleanerUtils.java

Line 31 in a59ea09

Class<?> cleanerClass = Class.forName(Jvm.isJava9Plus() ? "jdk.internal.ref.Cleaner" : "sun.misc.Cleaner");