Rather than relying on a `HOMEBREW_FORCE_BOTTLE` variable (which ends
up doing silly things like forcing bottle usage even when options are
provided) instead handle this at the `or_later` bottle detection
level so on prerelease versions of macOS any bottle looks like an
`or_later` bottle (unless various environment variables are set).
Fixes issues noted in:
https://github.com/Homebrew/brew/pull/4520#issuecomment-407229605