Replace native CryptoLib's verifyWithECDsa `curve` parameter by
`curveHash` parameter which is a enum over supported pairs of named
curves and hash functions.
Even though this change is a compatible extension of the protocol, it
changes the genesis state due to parameter renaming. But we're going to
resync chain in 3.7 release anyway, so it's not a big deal.
Also, we need to check mainnet and testnet compatibility in case if
anyone has ever called verifyWithECDsa with 24 or 25 `curve` value.
Signed-off-by: Anna Shaleva <shaleva.ann@nspcc.ru>
NewMerkleTree is a memory hog, we can do better than that:
BenchmarkMerkle/NewMerkleTree-8 13 88434670 ns/op 20828207 B/op 300035 allocs/op
BenchmarkMerkle/CalcMerkleRoot-8 15 69264150 ns/op 0 B/op 0 allocs/op
buildMerkleTree() is internal to the hash package and if anyone calls it with
`len(leaves) == 0` he deserves a panic. As it's the only error case in it, we
can remove error value return from this function and simplify NewMerkleTree().
Go's Hash is explicitly specified to never return an error on Write(), and our
own decoding functions only check for length which is gonna be right in every
case so it makes no sense returning errors from these functions.
