Double zip FlutterMacOS.framework.zip. (#41306)

This is required to make the artifact consistent with the legacy artifacts while the tool is modified to remove the need of double zipping.

Bug: https://github.com/flutter/flutter/issues/124911

[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style
diff --git a/sky/tools/create_macos_framework.py b/sky/tools/create_macos_framework.py
index 8f7a34c..8e194eb 100755
--- a/sky/tools/create_macos_framework.py
+++ b/sky/tools/create_macos_framework.py
@@ -172,6 +172,19 @@
         'without_entitlements.txt',
     ],
                           cwd=dst)
+    # Double zip to make it consistent with legacy artifacts.
+    # TODO(fujino): remove this once https://github.com/flutter/flutter/issues/125067 is resolved
+    subprocess.check_call([
+        'zip',
+        '-y',
+        'FlutterMacOS.framework_.zip',
+        'FlutterMacOS.framework.zip',
+    ],
+                          cwd=dst)
+    # Use doubled zipped file.
+    final_src_path = os.path.join(dst, 'FlutterMacOS.framework_.zip')
+    final_dst_path = os.path.join(dst, 'FlutterMacOS.framework.zip')
+    shutil.move(final_src_path, final_dst_path)
 
 
 if __name__ == '__main__':