Something really weird with this call. Seems as a mql error.

When I pass arguments to this function values as variables:

```
bool do_check_table_exists (string db, string table)
{
    int res = sqlite_table_exists (db, table);
```
I get the same pointer in db_filename and table_name, but only when I drop script on a chart. If it called from MetaEditor, it works ok.

But if I pass second argument as a constant string, it always works.

```
bool do_check_table_exists (string db, string table)
{
    int res = sqlite_table_exists (db, "test");
```