Don't use tointegerns when luaV_tointegerns will do

Some places don't need the "fast path" macro tointegerns, either
because speed is not essential (lcode.c) or because the value is not
supposed to be an integer already (luaV_equalobj and luaG_tointerror).
Moreover, luaV_equalobj should always use F2Ieq, even if Lua is
compiled to "round to floor".

ldebug.c

@@ -726,7 +726,7 @@ l_noret luaG_opinterror (lua_State *L, const TValue *p1,
 */
 l_noret luaG_tointerror (lua_State *L, const TValue *p1, const TValue *p2) {
   lua_Integer temp;
-  if (!tointegerns(p1, &temp))
+  if (!luaV_tointegerns(p1, &temp, LUA_FLOORN2I))
     p2 = p1;
   luaG_runerror(L, "number%s has no integer representation", varinfo(L, p2));
 }