Functorize `Ssa_builder`
Functorize `Ssa_builder`

Summary: For typechecking purposes we want to use `ALoc.t`, but other callers may prefer to use `Loc.t`.

Reviewed By: avikchaudhuri

Differential Revision: D12883982

fbshipit-source-id: 21d0c7b41c3996a51bc42ce508a3b2a2b86afaf6

AgentME/flow,popham/flow,facebook/flow,AgentME/flow,popham/flow,facebook/flow,mroch/flow,gabelevi/flow,samwgoldman/flow,samwgoldman/flow,popham/flow,AgentME/flow,mroch/flow,AgentME/flow,mroch/flow,facebook/flow,popham/flow,samwgoldman/flow,mroch/flow,gabelevi/flow,mroch/flow,facebook/flow,popham/flow,mroch/flow,gabelevi/flow,mroch/flow,popham/flow,gabelevi/flow,gabelevi/flow,facebook/flow,gabelevi/flow,AgentME/flow,samwgoldman/flow,samwgoldman/flow,facebook/flow,samwgoldman/flow,gabelevi/flow,facebook/flow,samwgoldman/flow,popham/flow