Test suite fails under Ubuntu 24.10 with libmariadb3-11.4.3

[paurkedal]

See this test result from #56:

Run sudo -u opam --preserve-env=OCAML_MARIADB_HOST,OCAML_MARIADB_PORT,OCAML_MARIADB_USER,OCAML_MARIADB_PASS,OCAML_MARIADB_DB opam exec -- dune runtest
File "tests/blocking/dune", line 2, characters 7-25:
2 |  (name blocking_testsuite)
           ^^^^^^^^^^^^^^^^^^
Stmt.close: (5025) Statement has no result set
File "tests/nonblocking-lwt/dune", line 2, characters 7-32:
2 |  (name nonblocking_testsuite_lwt)
           ^^^^^^^^^^^^^^^^^^^^^^^^^
Stmt.close: (5025) Statement has no result set
File "tests/nonblocking-async/dune", line 2, characters 7-34:
2 |  (name nonblocking_testsuite_async)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
Stmt.close: (5025) Statement has no result set
Error: Process completed with exit code 1.

I am not sure where the error comes from, as I can't find it in a checkout of the MariaDB release tag mariadb-11.4.3 or in the current repo, but it looks like the client library has become more strict about when a statement can be closed.