CMake auto-tests are not run automatically in the CI

Currently in Coin the cmake build system integration tests are not run. QTQAINFRA-2001 tracks re-enabling them in Coin, but in order for that to happen, the tests need to pass.

This is kind a bit of a chicken-and-egg problem and I suggest to initially change the build system in 5.6/5.9/5.11/dev to disable the tests on the build system level, re-enable running them in coin and then re-enable them on the build system level and fix failures as they appear.

An alternative would be to re-enable running them in coin but ignoring the results altogether. Then a second change in coin is needed after it's been verified that the tests are passing in all active Qt branches.

Edit: The agreed plan is to enable running the tests in Coin but ignore the result. Once tests are passing in all active branches, we must make them blocking.

Edit v2: To clarify, the acceptance criteria for this ticket is that the tests are enabled in such a way that a change that breaks the cmake tests will fail at the CI quality gate.