8273541: Cleaner Thread creates with normal priority instead of MAX_PRIORITY - 2

Reviewed-by: shade, alanb, lancea

src/java.base/share/classes/jdk/internal/ref/CleanerImpl.java

@@ -214,7 +214,7 @@ public final class CleanerImpl implements Runnable {
 
         public Thread newThread(Runnable r) {
             return InnocuousThread.newThread("Cleaner-" + cleanerThreadNumber.getAndIncrement(),
-                r, Thread.MIN_PRIORITY - 2);
+                r, Thread.MAX_PRIORITY - 2);
         }
     }