Remove gas computations from typechecker/normaliser?

[kwxm]

I see that the code in TypeCheck.Internal and Normalize.Internal contains gas computations. It seems unlikely that we're going to be doing typechecking on the chain, so should we remove the gas-related stuff eventually? That would simplify things a bit, which is probably good.

[michaelpj]

Yes, that seems likely.

[michaelpj]

We should also be able to remove the corresponding sections from the spec.