KT-83018 Introduce product for numeric collections

[Taskeren]

KT-83018

Implemented product() for numeric collections like sum()

[fzhinkin]

Assuming that implemented behavior (implicit integer overflow) is what we really want to achieve, the change would require tests and better documentation (detailed description of the behavior + samples) to be accepted. Currently, the code doesn't even compile.

Assuming that implemented behavior (implicit integer overflow) is what we really want to achieve

While implicitly overflowing would be consistent with sum's behavior, with multiplication the value grows significantly faster and it is much easier to hit the overflow. So other options should be considered, at least.

[Taskeren]

Assuming that implemented behavior (implicit integer overflow) is what we really want to achieve, the change would require tests and better documentation (detailed description of the behavior + samples) to be accepted. Currently, the code doesn't even compile.

Assuming that implemented behavior (implicit integer overflow) is what we really want to achieve

While implicitly overflowing would be consistent with sum's behavior, with multiplication the value grows significantly faster and it is much easier to hit the overflow. So other options should be considered, at least.

Maybe adding another product with return type of Long? what should it be called? productToLong()?

[Taskeren]

It should now compile, but when I try to add since declaration, it won't compile again. I'm not familiar with it, is it OK for this?
I'll continue to add test cases and more detailed documents later.