Issues with forRange

[B-rando1]

As I noted in #3991, Julia's ranges include the end value, whereas other languages do not. At first I thought we could get away with a quick fix of subtracting 1 from the given end value, but then I remembered that negative step values exist, and if step is negative we need to add 1 instead.

Furthermore, I looked at other generated code with negative step values (test cases for this do not currently exist; we will need to add some to main) in other langauges and realized that three other languages does not handle negative step values correctly either. Basically it's a similar issue to what we had in #3809, where our current implementations do not account for negative step.

What needs to be done:

• Julia: if step is positive, subtract 1 from end; if step is negative, add 1 to end.
• Java, C#, C++: change the inequality checking i so it's < when step is positive and > when step is negative.
• Python is fine, and Swift appears to be fine as well. I don't have Swift installed on my current machine, but I can install it to double-check at some point.

As with listSlice, we can make it so that if the value of step is known at generation-time, we generate more concise code. Otherwise we need to generate code to do that logic at runtime.

[JacquesCarette]

It feels to me that we need to look more deeply into what forRange means (and ought to mean) to make the rendering in each language more transparent.

I definitely agree with the last paragraph: we need to be clearer about what information is known when (this is something that @Xinlu-Y was working on, but it got very complicated rather quickly). We need to 'teach' our representations more about staging.

[B-rando1]

I made a PR to fix Julia's forRange for positive step values. Beyond that, there seems to be something of a rabbit-hole, so it might be best to leave it for now.