[testlib] put postgres test database in test/data/database directory with other (sqlite) test databases. Closes #9240765 Simplify .hgignore in passing.

[dataimport] make eids_seq_range as massive store instance attribute again I changed it to a class attribute recently, but on further thought (and prompting from Adrien) it seems to make more sense as an instance attribute.

[dataimport] stop supporting None as eids_seq_range It couldn't work as-is because entities_id_seq is not a sequence object.

[dataimport] remove eids_seq_start attribute from massive store Instead provide a utility function to reset the eid sequence.

[dataimport] massive store in slave mode shouldn't flush metadata The metadata insertion is to be done only by the master-mode store.

[dataimport] check that MassiveObjectStore restores the db schema properly Ideally we'd use "pg_dump --schema-only" to compare before/after, but when restoring a constraint such as: cstr48f9ceae537d68859b62c601681c8d3e CHECK (((cw_type)::text = ANY ((ARRAY['normal'::character varying, 'auto'::character varying])::text[]))) postgres will convert the text cast on array to a cast on each cell of array cstr48f9ceae537d68859b62c601681c8d3e CHECK (cw_type::text = ANY (ARRAY['normal'::character varying::text, 'auto'::character varying::text]))

[dataimport] split out listing indices/constraints from getting the corresponding query

[dataimport] massive_store: do not drop constraints multiple times It is now done in __init__.

[dataimport] massive_store: do not drop constraints with `cascade` since it breaks things We want to be able to restore constraints at the end of the import. If they are silently dropped due to a CASCADE, we can't do that.

[dataimport] massive_store: drop all constraints in __init__ and restore all in finish This should avoid dependency issues when dropping specific constraints (e.g. when dropping a primary constraint referenced by a foreign key constraint). We only do this in master mode, slave mode stores are supposed to work with an initialized db already.