8348800: Many serviceability/sa tests failing after JDK-8348239

Reviewed-by: shade, kevinw, lmesnik

Author: plummercj

src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/runtime/Threads.java

@@ -155,7 +155,11 @@ private static synchronized void initialize(TypeDataBase db) {
         virtualConstructor.addMapping("NotificationThread", NotificationThread.class);
         virtualConstructor.addMapping("StringDedupThread", StringDedupThread.class);
         virtualConstructor.addMapping("AttachListenerThread", AttachListenerThread.class);
-        virtualConstructor.addMapping("DeoptimizeObjectsALotThread", DeoptimizeObjectsALotThread.class);
+
+        /* Only add DeoptimizeObjectsALotThread if it is actually present in the type database. */
+        if (db.lookupType("DeoptimizeObjectsALotThread", false) != null) {
+            virtualConstructor.addMapping("DeoptimizeObjectsALotThread", DeoptimizeObjectsALotThread.class);
+        }
     }
 
     public Threads() {