Invoke JavaScript tests via CLI

[ford-at-aws]

User story

As example code engineer (internally) and customer (externally), I want a way to recursively execute all tests from a top-level directory using a single command (e.g. a language-specific test framework command, or a collection of commands located in shell script).

Did you say ALL tests?

Yes, but with a caveat: tests that are:

1. automation-friendly
2. currently working without intermittent failures.

You can isolate tests that fit the above criteria using tags (see Section 2 in this epic for more tag info).

What is "automation-friendly"?

This refers to tests are can be executed remotely in an Isengard account with no previous setup required. This would include both unit tests and integration tests.

Acceptance criteria

I know this is done when:

• I can demonstrate that all tests can be executed on your machine from the CLI (verify this) from the top-level.
• A single test command (or bash script containing tests) can invoke all tests successfully
• Any updated test steps are updated in the README

[cpyle0819]

This is handled in #4177