Add test vectors in BIP143 into tx_valid.json / sighash.json #14308

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AFAICT these test vectors aren't actually run bitcoin core, and other library developers use tx_valid.json/tx_invalid.json / sighash.json to test their implementations.

It looks like sighash.json hasn't been updated in 4 years (!)

https://github.com/bitcoin/bips/blob/master/bip-0143.mediawiki#example

This isn't a bad idea, and we could include the witnessV0 test vectors in the JSON file, but since sighash_tests.cpp only executes SignatureHash() and not SignatureHashSchnorr(), I don't think those test/data files should be considered complete anymore.

To test taproot validation on bcoin for example I created a fork of bitcoin that generated a taproot test vectors json file similar to the original files you are looking at (from #3975)

I think it's safe to close this as won't-fix for the reasons stated above. Pull requests are always welcome!