hardware/cpu: add virtualized? check

[p-linnane]

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This PR adds a check for virtualization, so we no longer have to use the ENV["HOMEBREW_GITHUB_ACTIONS"] hack to work around CI failures.

[p-linnane]

Thank you to @Bo98 for the idea & guidance here 🙇‍♂️

[Bo98]

Thanks!

[MikeMcQuaid]

Good idea @p-linnane!

[MikeMcQuaid]

so we no longer have to use the ENV["HOMEBREW_GITHUB_ACTIONS"] hack to work around CI failures.

@p-linnane although: please note on this that this should never be used in test do blocks as those should be consistent between CI and run on contributors' machines. No sense in having brew tests that aren't run in CI. For build differences: fair enough.

[p-linnane]

This is primarily to deal with things like OpenCL, which doesn't work on ephemeral ARM, or other GPU related things. Here's an example of a test update I made yesterday, and @Bo98 weighed in on adding this check: Homebrew/homebrew-core#160229

[Bo98]

Yeah OpenCL not working is not a CI limitation but rather a virtualisation limitation. So this is a more correct check than HOMEBREW_GITHUB_ACTIONS in those situations as it will be correct should anyone run the test in a local VM.

[MikeMcQuaid]

@p-linnane @Bo98 Gotcha, thanks, seems reasonable. I guess what I'm suggesting is that we avoid brew test lines that are never exercised in CI but that's not the case here 👍🏻