patch 9.0.0634: evaluating "expr" options has more overhead than needed

Problem:    Evaluating "expr" options has more overhead than needed.
Solution:   Use call_simple_func() for 'foldtext', 'includeexpr', 'printexpr',
            "expr" of 'spellsuggest', 'diffexpr', 'patchexpr', 'balloonexpr',
            'formatexpr', 'indentexpr' and 'charconvert'.
diff --git a/src/ex_docmd.c b/src/ex_docmd.c
index 9122039..09f0faf 100644
--- a/src/ex_docmd.c
+++ b/src/ex_docmd.c
@@ -5778,7 +5778,7 @@
 	if (expr != NULL)
 	{
 	    ++emsg_off;
-	    p = eval_to_string(expr, FALSE);
+	    p = eval_to_string(expr, FALSE, FALSE);
 	    --emsg_off;
 	    vim_free(expr);
 	}