patch 8.2.2198: ml_get error when resizing window and using text property

Problem:    ml_get error when resizing window and using text property.
Solution:   Validate botline of the right window. (closes #7528)
diff --git a/src/textprop.c b/src/textprop.c
index 5a18f6c..b6cae70 100644
--- a/src/textprop.c
+++ b/src/textprop.c
@@ -419,7 +419,7 @@
     int			i;
 
     // w_botline may not have been updated yet.
-    validate_botline();
+    validate_botline_win(wp);
     for (lnum = wp->w_topline; lnum < wp->w_botline; ++lnum)
     {
 	count = get_text_props(wp->w_buffer, lnum, &props, FALSE);