Automatically de-`Constant` tuple arguments

[AntonOresten]

Something like a dispatching on Tuple{Vararg{IntOrConstInt}} for load, reshape, etc. to avoid having to explicitly get the value parameter from the Constant with e.g. tm[]. Currently one can assign separate variables or do kernel(::ConstInt{tm}) where tm to achieve this. I find the latter nicer to parse but both are a bit verbose compared to Python.

[maleadt]

Constants are pretty fundamentally different from regular parameters, since they force recompilation. We could make something behave scalar-like, but it'll always be a fundamentally different thing. Meaning you can't pass it to a function expecting an Int, like all of our indexing arguments. We could create loads of aliases like ConstInt <: Integer, but that (to me) indicates that the mechanism is not generic enough. And it wouldn't work with e.g. Base indexing methods expecting Int.

Meanwhile, const_int[]::Int unambiguously produces an Int, which is compatible with everything.

---

Maybe we could do something different though. Like automatically generating a wrapper function that fetches the constant value and "passes" it to the kernel function which then would see an actual constant. Disadvantage: it would pretty heavily rely on constant propagation to make sure that constant isn't materialized in the IR; but that's probably something we can handle at the Julia or Tile IR codegen level.