Decrease SegWit activation height on regtest

[alexbosworth]

For tests, it would be helpful if SegWit could be utilized on regtest with fewer blocks mined

[jakesylvestre]

I think if we did this it'd need to be a variable/config override

[alexbosworth]

I think Bitcoin Core did something similar for their regtest but I don't know the details

[alexbosworth]

Are there still people testing non-SegWit things? Why not just activate it from the start like Signet

[jakesylvestre]

It would appear regtest is always active on bitcoin-core: https://github.com/bitcoin/bitcoin/blob/5961b23898ee7c0af2626c46d5d70e80136578d3/src/chainparams.cpp#L295 There's a discussion on another client here: stratisproject/StratisBitcoinFullNode#1028. I woudn't be opposed to activating it from the start if you want to submit a pr.

@Roasbeef/@jcvernaleo - lmk if you have any objections here. I really can't think of any

Honestly, we could probably implement this in #1692

[jcvernaleo]

I have no objection. Makes a lot of sense to me actually.