Move variable increment to the end of the loop

This is less error prone and matches the placement of other code
in the file.

Justin Pryzby

Reviewed by Tom Lane
Discussion: https://www.postgresql.org/message-id/20221123172436.GJ11463@telsasoft.com

src/backend/utils/activity/backend_status.c

@@ -842,7 +842,6 @@ pgstat_read_current_status(void)
 			CHECK_FOR_INTERRUPTS();
 		}
 
-		beentry++;
 		/* Only valid entries get included into the local array */
 		if (localentry->backendStatus.st_procpid > 0)
 		{
@@ -871,6 +870,8 @@ pgstat_read_current_status(void)
 #endif
 			localNumBackends++;
 		}
+
+		beentry++;
 	}
 
 	/* Set the pointer only after completion of a valid table */