[Bug][CI] integration tests not currently running in ci_gpu image

[leandron]

When looking at recent CI test run (which I'm enabling torch/ONNX tests on AArch64), I noticed an issue with a missing transformers package while executing test_meta_schedule_integration_extract_from_bert_base , causing the integration tests to fail on AArch64.

Investigating the issue a bit deeper, it seems that integration tests are not running on ci_GPU image, which is the one that is supposed to contain torch and therefore would reproduce the problem.

I'm raising this issue just because I won't have the time in the next weeks to enable that package and test the GPU image and test it to solve the problem. So I create this PR #12528 to make the test to be properly skipped if transformers is not installed, but leaving this issue so that we can investigate two potential problems:

1. Integration tests not running in the GPU environment
2. Missing transformers installation, if that is what we want (pending to be confirmed, I didn't fully investigate)

cc @Mousius @areusch @driazati @gigiblender

[leandron]

ONNX testing that runs as part of Integration tests is also not running anywhere. One is actually broken, #12532

[areusch]

@gigiblender is it possible to leverage #12436 to add another GH check to assert we aren't skipping a couple of critical integration tests in a PR?

[gigiblender]

@gigiblender is it possible to leverage #12436 to add another GH check to assert we aren't skipping a couple of critical integration tests in a PR?

Sure thing. We could change that script to pass a list of critical tests to ensure that some tests are not skipped and call it in a GH check. Let me know if that sounds right.