[18.10] Revert "Merge branch 'segregate-buildx-build-among-rails-ce-and-ee' into 'master'"

What does this MR do and why?

Revert "Merge branch 'segregate-buildx-build-among-rails-ce-and-ee' into 'master'"

This reverts merge request !2701 (merged)

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• This MR is backporting a bug fix, documentation update, or spec fix, previously merged in the default branch.
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• This MR has a severity label assigned (if applicable).

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