ole32: Make get_priv_data return target device ptrs (rather than offsets) and add a couple of helper functions to simplify this process.

Remove the untranslated and incomplete STRINGTABLE.

parser_alloc() allocates memory and puts it on a list attached the to query object.
EXPR_sval() frees memory allocated via parser_alloc() on error but does not remove
the pointer from the list, which means that when the query destructor is called it
will be freed again.

TABLE_drop() calls TABLE_remove_column() which calls msi_update_table_columns()
which frees column info and possibly returns without reallocating. When that
happens it will be freed again when TABLE_drop() finally calls free_table().