refactor[venom]: refactor sccp pass to use dfg

[HodanPlodky]

What I did

used DFGAnalysis in SCCP instead of the computing the uses in the SCCP itself

How I did it

Remove computation from the SCCP and added DFG analysis into it and changed the DFG analysis so it uses OrderedSet

How to verify it

Commit message

use `DFGAnalysis` in `SCCP` instead of duplicating the logic to compute
uses in the `SCCP` itself. also use `OrderedSet` for var uses, this
ensures we don't add the same instruction multiple times (as in `add
%2 %2`) to a var's use set, and also enables a cheaper `remove_use()`
implementation.

Cute Animal Picture

[charles-cooper]

i was looking at this and i think technically we don't even need dominator analysis, we just use it for dfs walk