improved docker test environment

[osteensco]

I was working on my old crappy macbook and ran into some issues related to docker-compose and my os just being kinda old. To get around this I repurposed the windows_test_env to be more flexible. It's been renamed to test_env and has the following -

• all: make testenv-all runs both test and test-race sequentially like the original dockerfile did before.
• test: make testenv-test runs make test only.
• test_race: make testenv-test-race runs make test-race only.
• run: make testenv-run builds and runs a docker container in interactive mode. This allows for easier debugging of a single test or group of tests as well as allows easy execution other commands/scripts like make benchmark. This container will not update the projects coverage.out.