patch 8.2.0204: crash when using winnr('j') in a popup window

Problem:    Crash when using winnr('j') in a popup window.
Solution:   Do not search for neighbors in a popup window. (closes #5568)
diff --git a/src/evalwindow.c b/src/evalwindow.c
index fb54033..be6762a 100644
--- a/src/evalwindow.c
+++ b/src/evalwindow.c
@@ -332,8 +332,6 @@
 	else if (STRCMP(arg, "#") == 0)
 	{
 	    twin = (tp == curtab) ? prevwin : tp->tp_prevwin;
-	    if (twin == NULL)
-		nr = 0;
 	}
 	else
 	{
@@ -360,6 +358,8 @@
 	    else
 		invalid_arg = TRUE;
 	}
+	if (twin == NULL)
+	    nr = 0;
 
 	if (invalid_arg)
 	{