patch 8.2.4739: accessing freed memory after WinScrolled autocmd event

Problem:    Accessing freed memory after WinScrolled autocmd event.
Solution:   Check the window pointer is still valid. (closes #10156)
            Remove the argument from may_trigger_winscrolled().
diff --git a/src/main.c b/src/main.c
index fe3571b..036ab0a 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1342,7 +1342,7 @@
 	    validate_cursor();
 
 	    if (!finish_op)
-		may_trigger_winscrolled(curwin);
+		may_trigger_winscrolled();
 
 	    // If nothing is pending and we are going to wait for the user to
 	    // type a character, trigger SafeState.