cmd/compile/internal/types: simplify iterating all parameters
The types.RecvsParamsResults, etc. helpers existed to make it "easier"
to iterate over all parameters, or recvs+params, or params+results;
but they end up still being quite clumsy to use due to the design goal
of not allocating temporary slices.
Now that recvs+params+results are stored in a single consecutive slice
anyway, we can just return different subslices and simplify the loops.
Change-Id: I84791b80dc099dfbfbbe6eddbc006135528c23b4
Reviewed-on: https://go-review.googlesource.com/c/go/+/521375
Auto-Submit: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com> Reviewed-by: Than McIntosh <thanm@google.com>