This is primarily intended to resolve the `uninitialized constant
Utils::Backtrace` error in `formula_versions.rb:60` but I expanded it
to try to cover all existing usage of `Utils::Backtrace`.
I've followed the existing pattern, where `utils/backtrace` is
required in the context of where it's used. Many of these cases use
`Backtrace` in a conditional manner, so I've tried to ensure that the
`require` follows suit.
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