Broken Dockerfile in benchmarks

[GitSparTV]

The archive in README for benchmark tests doesn't build successfully.
At the current moment container requires absl, ./build.sh instead of sh build.sh, updated pkg-config, recursive clone of re2 and many other things.

[genivia-inc]

The Dockerfile worked years ago, but probably needs updating. So I can't guarantee the containerized version. But manually it works fine.

For the manual test, all libraries must be installed first and RE/flex should be built before compiling and running the tests using make and run.sh.

I'm not in a hurry to update the Dockerfile, which was just included for convenience, since the tests can be run on a Linux box w/o container. Maybe I should remove the Dockerfile if it's not maintainable.