HPCC-21743 PERSIST('Thread') is not working correctly in Java embed 7.2.0-rc2

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>

plugins/javaembed/javaembed.cpp

@@ -4329,6 +4329,9 @@ protected:
         ret.append(classname).append('.');
         switch (persistMode)
         {
+        case persistThread:
+            ret.append(__uint64(GetCurrentThreadId()));
+            break;
         case persistGlobal:
             ret.append("global");
             break;