fix: duplicate ninja rules for v8 (cross-compiling)

[moto-timo]

avoids duplicate ninja rules for v8 used in host and target

From: https://github.com/minrk/node/commit/5e533cb943eef68b270f55f0cba02c0ec67c699d

Reported in https://github.com/nodejs/node/issues/46690 and https://github.com/nodejs/node/issues/37441

[cclauss]

Please rebase.

[moto-timo]

Rebased again.

[moto-timo]

Rebased to pick up the xml.etree.cElementTree commit.

[moto-timo]

@cclauss I believe I addressed your recommendations and rebase concerns. Anything else that needs to be done or any more discussion?

[cclauss]

This pull request is rebased and the tests are all green. ✅ Thanks for that.

Now what we need is some maintainer who has enough expertise to review and approve or make suggestions.

[moto-timo]

@cclauss great. Thank you for the response.

[ryzokuken]

I can confirm that this goes with the default naming conventions of depot_tools and ninja, but I'd let someone else approve it for sure.