Merge pull request #12433 from richardkchapman/java-persistthread

HPCC-21894 Persist(THREAD) not properly reset when thread reused

Reviewed-by: Gavin Halliday <ghalliday@hpccsystems.com>

plugins/javaembed/javaembed.cpp

@@ -3099,6 +3099,12 @@ public:
     }
     ~JavaEmbedImportContext()
     {
+        if (persistMode == persistThread)
+        {
+            StringBuffer scopeKey;
+            getScopeKey(scopeKey);
+            JavaGlobalState::unregister(scopeKey);
+        }
         if (javaClass)
             JNIenv->DeleteGlobalRef(javaClass);
         if (classLoader)