Tax group are currently ordered by sequence only.
Only 2 localizations of ours have defined the sequence on them.
So, most of the tax groups have the same sequence.
The order of search made on them is thus undeterministic.
It can be seen when running the test test_generate_xml_sale with
l10n_ee_reports installed, it fails sometimes (1 in 50 to 100).
Because the invoice amounts are grouped and ordered by tax groups.

Linked to runbot error 24595

closes odoo/odoo#137686

Signed-off-by: de Wouters de Bouchout Jean-Benoît (jbw) <jbw@odoo.com>