Run unit tests on linux

[lstocchi]

b525dc8#r1909010646 updated the gh workflow to run tests. However, it causes some tests to not being run anymore.
This patch re-add back the test command and filters the vfkit tests using the go build tag

it fixes #452

[cfergeau]

/lgtm
/approve

These testing targets deserve a larger overhaul at some point. We should be running all the tests which do not need virtualization on macos/linux/windows, and then run the tests which require virtualization on a linux runner since it is the only place where they can run.

[openshift-ci]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: cfergeau, lstocchi

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[cfergeau]

These testing targets deserve a larger overhaul at some point. We should be running all the tests which do not need virtualization on macos/linux/windows, and then run the tests which require virtualization on a linux runner since it is the only place where they can run.

I created #458 to track this.