patch 8.2.0118: crash when cycling to buffers involving popup window

Problem:    Crash when cycling to buffers involving popup window .
Solution:   Do not decrement buffer reference count.
diff --git a/src/popupwin.c b/src/popupwin.c
index c6296df..e1f73bd 100644
--- a/src/popupwin.c
+++ b/src/popupwin.c
@@ -937,10 +937,7 @@
 
     nr = dict_get_number(dict, (char_u *)"hidden");
     if (nr > 0)
-    {
 	wp->w_popup_flags |= POPF_HIDDEN;
-	--wp->w_buffer->b_nwindows;
-    }
 
     popup_mask_refresh = TRUE;
     popup_highlight_curline(wp);
@@ -1153,7 +1150,6 @@
 	    if ((wp->w_popup_flags & POPF_HIDDEN) == 0)
 	    {
 		wp->w_popup_flags |= POPF_HIDDEN;
-		--wp->w_buffer->b_nwindows;
 		if (win_valid(wp->w_popup_prop_win))
 		    redraw_win_later(wp->w_popup_prop_win, SOME_VALID);
 	    }
@@ -2351,7 +2347,7 @@
     if ((wp->w_popup_flags & POPF_HIDDEN) == 0)
     {
 	wp->w_popup_flags |= POPF_HIDDEN;
-	--wp->w_buffer->b_nwindows;
+	// Do not decrement b_nwindows, we still reference the buffer.
 	redraw_all_later(NOT_VALID);
 	popup_mask_refresh = TRUE;
     }
@@ -2376,7 +2372,6 @@
     if ((wp->w_popup_flags & POPF_HIDDEN) != 0)
     {
 	wp->w_popup_flags &= ~POPF_HIDDEN;
-	++wp->w_buffer->b_nwindows;
 	redraw_all_later(NOT_VALID);
 	popup_mask_refresh = TRUE;
     }
@@ -3154,7 +3149,6 @@
 							   &prop, &lnum) == OK)
 	{
 	    wp->w_popup_flags &= ~POPF_HIDDEN;
-	    ++wp->w_buffer->b_nwindows;
 	    wp->w_popup_prop_topline = 0; // force repositioning
 	    return TRUE;
 	}