Running tests with intsize64=on build

[gmargari]

Hi there guys, and thank you for this immensely helpful project!

I compiled MUMPS 5.6.1 on Linux using MKL 2023.1, enabling also complex libs.
When intsize64=off, all 4 test complete successfully (test_mumps_{config,simple32,simple64,complex128}).
When intsize64=on, the test_mumps_complex128 test fails.

Is this something to be expected?
If I understand correctly, the tests are disabled in you github actions so I am not sure what should be the expected outcome.

Note: tests pass successfully with MUMPS 5.7.3.

Thanks again,
Giorgos