Here's the second half of adding a migration compatibility test to CI.

We've already added support for running the full set of migration
tests with two QEMU binaries since commit 5050ad2a380
("tests/qtest/migration: Support more than one QEMU binary"), now
what's left is adding it to the CI.

I included patches that solve the problem of testing older QEMUs with
new test code. The old QEMU might lack features, bug fixes, etc. that
the tests expect to be present. After this series we can specify a
minimal QEMU version that a specific test supports.

changes since v2:
 - fixed version comparison once again

 - removed the 8.2 fixes. We don't need them anymore because we're now
   testing two 8.2 streams (8.2.0 vs. 8.2.50).

CI run: https://gitlab.com/farosas/qemu/-/pipelines/1128168149

v2:
https://lore.kernel.org/r/20240104171857.20108-1-farosas@suse.de

v1:
https://lore.kernel.org/r/20231207155809.25673-1-farosas@suse.de

Fabiano Rosas (4):
  tests/qtest: Add a helper to query the QEMU version
  tests/qtest/migration: Add infrastructure to skip tests on older QEMUs
  ci: Add a migration compatibility test job
  [NOT FOR MERGE] tests/qtest/migration: Adapt tests to use older QEMUs

 tests/qtest/libqtest.h          | 10 ++++++
 tests/qtest/migration-helpers.h |  1 +
 tests/qtest/libqtest.c          | 24 +++++++++++++
 tests/qtest/migration-helpers.c | 48 +++++++++++++++++++++++++
 tests/qtest/migration-test.c    | 63 +++++++++++++++++++++++++++++----
 .gitlab-ci.d/buildtest.yml      | 53 +++++++++++++++++++++++++++
 6 files changed, 192 insertions(+), 7 deletions(-)

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2.35.3