Log Message:
Update at-spi2-core to 2.25.1

This has several fixes which aren't in the "stable" 2.24.1

What's new in at-spi2-atk 2.25.1:

* Fix position getter for table cells.
* Fix memory corruption when deleting an event from the list of events
  for which there are registered listeners (bgo#781658).

What's new in at-spi2-atk 2.24.0:

* test: remove atk_table_cell_get_column_index test, as the
  at-spi2-core function no longer exists (and never worked anyhow).