patch 9.0.0927: Coverity warns for using a NULL pointer

Problem:    Coverity warns for using a NULL pointer.
Solution:   Check for memory allocaion failure.
diff --git a/src/version.c b/src/version.c
index c9e3a2e..6e0d886 100644
--- a/src/version.c
+++ b/src/version.c
@@ -696,6 +696,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    927,
+/**/
     926,
 /**/
     925,
diff --git a/src/window.c b/src/window.c
index 48eabda..6816697 100644
--- a/src/window.c
+++ b/src/window.c
@@ -3134,7 +3134,7 @@
 #endif
     }
 
-    if (trigger_scroll)
+    if (trigger_scroll && scroll_dict != NULL)
     {
 #ifdef FEAT_EVAL
 	save_v_event_T  save_v_event;