Seeded an off-by-one bug

[zvonimir]

Seeded what I think is a reasonable bug into this benchmark to create some benchmarks with bugs in this category.
It is a first step towards doing #1183.
If people are reasonably happy with this one, I'll do more.

[zvonimir]

This is the diff with the original file:

7894c7894
<     for (size_t i = 0; i < array_len; ++i) {
---
>     for (size_t i = 0; i < array_len - 1; ++i) {

[dbeyer]

Nice addition.

[dbeyer]

I am merging, but I thought about the following:

• Is there a way to document the bug in the code, that is, can you add a C comment above the line
  that states that this is the bug?
• How to track the change in the .c file / original sources?

Could you please address this in a separete PR? (I do not want to hold it back because people obviously want to play around with it.)

[zvonimir]

@dbeyer good suggestions! I'll add a comment with each bug I seed.
Btw, where are the original .c sources? I can't find them anywhere in the repo, but maybe I missed them.