Re-write integration tests to use the new `corepc` stack

[tcharding]

As we did in miniscript we should upgrade the integration tests to use the new stack of corepc crates.

ref: https://crates.io/search?q=corepc

[nyonson]

Gonna try and use the corepc-node approach we took in https://github.com/rust-bitcoin/bip324/blob/main/protocol/tests/round_trips.rs. I don't think a separate crate for tests is technically required right?

[nyonson]

Ah, but seeing now how a separate testing crate might be necessary in order to test different versions of bitcoind without really polluting the end-user feature flags.

[tcharding]

BOOM! Thanks man, nice to have validation.