fix!: limit monero hashes and force coinbase to be tx 0

[SWvheerden]

Description

This limits the merkle proof hashes from monero blocks to be all used stopping miners from adding junk data at the end that is not used.
Also brings the merkle root construction inline with monero rule by forcing the coinbase to be tx 0.

Motivation and Context

If the hashes are not limited, miners can add endless data to the header. This causes TARI-006 and TARI-008, TARI-009, TARI-011 and TARI-012

How Has This Been Tested?

Unit tests

Audit Finding Number

TARI-006
TARI-008
TARI-009
TARI-011
TARI-012

[github-actions]

Test Results (CI)

1 189 tests   1 189 ✔️  32m 20s ⏱️
     37 suites         0 💤
       1 files           0 ❌

Results for commit 884d33b.

♻️ This comment has been updated with latest results.

[github-actions]

Test Results (Integration tests)

27 tests   27 ✔️  16m 20s ⏱️
11 suites    0 💤
  2 files      0 ❌

Results for commit 884d33b.

♻️ This comment has been updated with latest results.

[sdbondi]

ACK

was initially worried about some of the test code removal but I see it's only the code that tests proofs for arbitrary tx hashes 👍

[sdbondi]

While checking things I added 2 hashes to this test. Up to you if you want to add it, not NB. Obviously if you do you'll need to update/remove the "diagram" :)

   let hashes = (1..=8).map(|i| Hash::from([i; 32])).collect::<Vec<_>>();
            let h23 = cn_fast_hash2(&hashes[2], &hashes[3]);
            let h45 = cn_fast_hash2(&hashes[4], &hashes[5]);
            let h67 = cn_fast_hash2(&hashes[6], &hashes[7]);
            let h01 = cn_fast_hash2(&hashes[0], &hashes[1]);
            let h0123 = cn_fast_hash2(&h01, &h23);
            let h4567 = cn_fast_hash2(&h45, &h67);
            let expected_root = cn_fast_hash2(&h0123, &h4567);

            // Proof for h0
            let proof = create_merkle_proof(&hashes).unwrap();
            assert_eq!(proof.calculate_root(&hashes[0]), expected_root);
            assert_eq!(proof.branch().len(), 3);
            assert_eq!(proof.branch()[0], hashes[1]);
            assert_eq!(proof.branch()[1], h23);
            assert_eq!(proof.branch()[2], h4567)

[brianp]

utAck