Add DispatchPonyCtx optimisation pass (#887)
Add DispatchPonyCtx optimisation pass (#887)

A Dispatch function has a pony_ctx_t in its parameters. This
optimisation pass replaces pony_ctx calls in Dispatch functions (mostly
generated by inlining user functions) with uses of the parameter.
Praetonus/ponyc,boemmels/ponyc,boemmels/ponyc,sgebbie/ponyc,jupvfranco/ponyc,dipinhora/ponyc,dipinhora/ponyc,Praetonus/ponyc,kulibali/ponyc,jemc/ponyc,boemmels/ponyc,Theodus/ponyc,Perelandric/ponyc,sgebbie/ponyc,Perelandric/ponyc,lukecheeseman/ponyta,jemc/ponyc,kulibali/ponyc,ponylang/ponyc,ryanai3/ponyc,CausalityLtd/ponyc,boemmels/ponyc,Theodus/ponyc,jupvfranco/ponyc,sgebbie/ponyc,jupvfranco/ponyc,mkfifo/ponyc,malthe/ponyc,ryanai3/ponyc,Theodus/ponyc,lukecheeseman/ponyta,boemmels/ponyc,jupvfranco/ponyc,Perelandric/ponyc,mkfifo/ponyc,Perelandric/ponyc,mkfifo/ponyc,kulibali/ponyc,malthe/ponyc,jupvfranco/ponyc,Perelandric/ponyc,malthe/ponyc,CausalityLtd/ponyc,kulibali/ponyc,sgebbie/ponyc,mkfifo/ponyc,cquinn/ponyc,ponylang/ponyc,mkfifo/ponyc,ryanai3/ponyc,Praetonus/ponyc,jemc/ponyc,malthe/ponyc,cquinn/ponyc,CausalityLtd/ponyc,Theodus/ponyc,cquinn/ponyc,Theodus/ponyc,Praetonus/ponyc,ponylang/ponyc,sgebbie/ponyc,dipinhora/ponyc,cquinn/ponyc,lukecheeseman/ponyta