Add missing shootout benchmarks

[kud1ing]

A Rust implementation for these are missing:

(now empty)

[killerswan]

I'm going to give chameneos-redux a shot this afternoon.

[kud1ing]

Regular Expression issue is #3591

[brson]

We need a new threadring too: #4177

[bstrie]

I see implementations of pidigits and reverse-complement, but we still appear to need meteor and regex-dna.

[emberian]

See also #7532

[bstrie]

@satwiki I remember you saying that you were interested in writing benchmarks, and this would be the perfect one to start on. I also made a tag in the bug tracker, "A-benchmarks", for this sort of thing and populated it with a few issues that you can also look at.

[pnkfelix]

Accepted for P-low.

[dcampbell24]

Looking at the current code base there appears to be implementations for all of the shootout benchmarks. Can anyone elaborate on what work is left to be done?

[kud1ing]

@davekong: It seems, you are right.