update: check-in test data, add new test options, reduce test flakyness for Falco

[jasondellaluce]

• Adds support for setting a Context and environment variables for runners.
• Checks in test data (conf files, rules files, outputs) that used to be downloaded and generated with go generate. This makes the codebase easier to navigate and allows customizing the test data, which was previously taken as-is from old commits of the Falco repo.
• Reduces the flakyness of Falco tests regarding strict checks on the outputs (stdout, file, program), and improves the execution of the gRPC tests

For the reviewer: please disregard all files under tests/data, since they are the result of previously-generated test data and are responsible for most of the LOC of this PR.

[poiana]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Andreagit97, jasondellaluce

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Needs approval from an approver in each of these files: - ~~[OWNERS](https://github.com/falcosecurity/testing/blob/main/OWNERS)~~ [Andreagit97,jasondellaluce] Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment

[poiana]

LGTM label has been added.

Git tree hash: 7066bef3884a414d4ccabb53ef16086caa8f1c5f