Time sort to determine reasonable test array length.

Add ability to time sort.

Report if test failures.

Remove unnecessary includes.

array_type enum is part of the test.

Export only the test helper functions we need.

Use size_t and ssize_t where appropriate throughout.

Separate out test run code.

Move test helper functions to separate file.

Use function prefix to avoid conflicts.

Refactor testing code and allow testing of array types other than reverse sorted.

Make comment markdown-y.

Move description to more sensible location, remove duplicated comments.

Use better variable name for array length.

Use const where it makes sense to.