Make AppIntentsMetadataProcessor outputs deterministic

[thelvis4]

We noticed that xcrun appintentsmetadataprocessor produces non-deterministic Metadata.appintents/extract.actionsdata and Metadata.appintents/version.json JSON outputs (unstable json key order) resulting in different hashes for them when building the same target on different machines.

Tree Digest: root:  {
  files:  {
    name:  "extract.actionsdata"
    digest:  {
      hash:  "1a5948b0129723785ddccd42ec3e6f0315d43dbb77db291c890cf314b0f42b1b"
      size_bytes:  2981
    }
    is_executable:  true
  }

Tree Digest: root:  {
  files:  {
    name:  "extract.actionsdata"
    digest:  {
      hash:  "278dbe486ed21bebe61a5fef6dab2be05ba5fae588d7b330eb0200b8300e23e9"
      size_bytes:  2981
    }
    is_executable:  true
  }

Changes
Sort the keys of Metadata.appintents/extract.actionsdataand Metadata.appintents/extract.actionsdata directory tree output using /usr/bin/python3 -m json.tool to make it deterministic.

Filed Apple Feedback: FB19585633
Fixes #2760

[aaronsky]

I'm not crazy about relying on the toolchain's Python here – normally I would prefer this live in a tool declared in a py_binary. That being said, I acknowledge that you're mainly working within the existing code here, and that json.tool hasn't meaningfully changed in several years now, so it's not the worst idea.

[thelvis4]

Right, given the action depends on DEVELOPER_DIR and is invalidated when Xcode version changes, I figured I can call python3 shipped with Xcode. It reduces the amount of code needed to pass the python binary and makes it easier to remove the mitigation after Apple fixes the root issue.

[adincebic]

I would take this change as is. @aaronsky do you feel strongly about py_binary here?

[adincebic]

Thanks for fixing this.