patch 8.1.1957: more code can be moved to evalvars.c

Problem:    More code can be moved to evalvars.c.
Solution:   Move code to where it fits better. (Yegappan Lakshmanan,
            closes #4883)
diff --git a/src/session.c b/src/session.c
index 473d94f..7139c52 100644
--- a/src/session.c
+++ b/src/session.c
@@ -500,13 +500,14 @@
     static int
 store_session_globals(FILE *fd)
 {
+    hashtab_T	*gvht = get_globvar_ht();
     hashitem_T	*hi;
     dictitem_T	*this_var;
     int		todo;
     char_u	*p, *t;
 
-    todo = (int)globvarht.ht_used;
-    for (hi = globvarht.ht_array; todo > 0; ++hi)
+    todo = (int)gvht->ht_used;
+    for (hi = gvht->ht_array; todo > 0; ++hi)
     {
 	if (!HASHITEM_EMPTY(hi))
 	{