ADTs with hole type consistency have casting bug

[gensofubi]

I expect both examples to work alright but one gives exceptions and the other is stucked.

[Negabinary]

I just now pushed a quick fix to get this example working on that branch (https://hazel.org/build/remove-dhexp/).

I've changed a lot of how elaboration and pattern matching work on the #1197 branch. I think if we want to fix it on dev, it'll be somewhere in the matches cast sum function in PatternMatch.re. Hopefully #1197 will get merged soon though, so we may not need to do it on dev?

[Negabinary]

Fixed in #1197