dependency_collector: distinguish macOS deps by OS

[EricFromCanada]

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---

uses_from_macos dependencies need to indicate their OS bounds when being cached. Fixes #15907.

$ HOMEBREW_NO_INSTALL_FROM_API=1 brew info gitless glib --json | jq '.[].uses_from_macos_bounds'
[
  {}
]
[
  {
    "since": "catalina"
  },
  {
    "since": "catalina"
  }
]

$ HOMEBREW_NO_INSTALL_FROM_API=1 brew info glib gitless --json | jq '.[].uses_from_macos_bounds'
[
  {
    "since": "catalina"
  },
  {
    "since": "catalina"
  }
]
[
  {}
]

[EricFromCanada]

There's probably a better way to do this, but this seems to work.

[Bo98]

I think a better way is to fix def hash and def == in UsesFromMacOSDependency.

The change here looks to regress in the case of differing tags.

[MikeMcQuaid]

Sorry, enabled auto-merge before I saw your comment @Bo98.

[MikeMcQuaid]

Great catch @EricFromCanada, thanks!