Avoid intern calls for builtin syms

* src/casefiddle.c (Fdowncase_region):
* src/eval.c (Fdefvaralias):
Use builtin symbol rather than calling intern.

src/casefiddle.c

@@ -529,7 +529,7 @@ See also `capitalize-region'.  */)
 
   if (!NILP (region_noncontiguous_p))
     {
-      bounds = call1 (Fsymbol_value (intern ("region-extract-function")),
+      bounds = call1 (Fsymbol_value (Qregion_extract_function),
 		      intern ("bounds"));
 
       while (CONSP (bounds))

src/eval.c

@@ -625,7 +625,7 @@ The return value is BASE-VARIABLE.  */)
            && !EQ (find_symbol_value (new_alias),
                    find_symbol_value (base_variable)))
     call2 (intern ("display-warning"),
-           list3 (intern ("defvaralias"), intern ("losing-value"), new_alias),
+           list3 (Qdefvaralias, intern ("losing-value"), new_alias),
            CALLN (Fformat_message,
                   build_string
                   ("Overwriting value of `%s' by aliasing to `%s'"),