move default_prefix to extend/os

Library/Homebrew/default_prefix.rb

@@ -1,15 +1,7 @@
 # typed: true
 # frozen_string_literal: true
 
-require "simulate_system"
-
 module Homebrew
-  # TODO: Refactor and move to extend/os
-  DEFAULT_PREFIX, DEFAULT_REPOSITORY = if OS.mac? && Hardware::CPU.arm? # rubocop:disable Homebrew/MoveToExtendOS
-    [HOMEBREW_MACOS_ARM_DEFAULT_PREFIX, HOMEBREW_MACOS_ARM_DEFAULT_REPOSITORY]
-  elsif Homebrew::SimulateSystem.simulating_or_running_on_linux?
-    [HOMEBREW_LINUX_DEFAULT_PREFIX, HOMEBREW_LINUX_DEFAULT_REPOSITORY]
-  else
-    [HOMEBREW_DEFAULT_PREFIX, HOMEBREW_DEFAULT_REPOSITORY]
-  end.freeze
+  DEFAULT_PREFIX = HOMEBREW_DEFAULT_PREFIX
+  DEFAULT_REPOSITORY = HOMEBREW_DEFAULT_REPOSITORY
 end

Library/Homebrew/extend/os/default_prefix.rb

@@ -0,0 +1,10 @@
+# typed: true
+# frozen_string_literal: true
+
+require "simulate_system"
+
+if OS.mac? && Hardware::CPU.arm?
+  require "extend/os/mac/default_prefix"
+elsif Homebrew::SimulateSystem.simulating_or_running_on_linux?
+  require "extend/os/linux/default_prefix"
+end

Library/Homebrew/extend/os/linux/default_prefix.rb

@@ -0,0 +1,7 @@
+# typed: true
+# frozen_string_literal: true
+
+module Homebrew
+  DEFAULT_PREFIX = HOMEBREW_LINUX_DEFAULT_PREFIX
+  DEFAULT_REPOSITORY = HOMEBREW_LINUX_DEFAULT_REPOSITORY
+end

Library/Homebrew/extend/os/mac/default_prefix.rb

@@ -0,0 +1,7 @@
+# typed: true
+# frozen_string_literal: true
+
+module Homebrew
+  DEFAULT_PREFIX = HOMEBREW_MACOS_ARM_DEFAULT_PREFIX
+  DEFAULT_REPOSITORY = HOMEBREW_MACOS_ARM_DEFAULT_REPOSITORY
+end