os/mac/xcode: fix latest Xcode on Big Sur

[Bo98]

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Fixes #13041.

[BrewTestBot]

Review period skipped due to critical label.

[rtrys]

@Bo98 I'm facing this error when I install homebrew

==> Downloading and installing Homebrew...
HEAD is now at 5b787e2e3 Merge pull request #13042 from Bo98/xcode-big-sur
error: Not a valid ref: refs/remotes/origin/master
fatal: ambiguous argument 'refs/remotes/origin/master': unknown revision or path not in the working tree.
Use '--' to separate paths from revisions, like this:
'git <command> [<revision>...] -- [<file>...]'

could be any relation with this branch?

EDIT: I'm trying to install homebrew in mac os Monterrey (12.3) by running this command

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"