Find and add relevant test suites to the project

[oleiade]

With EcmaScript, and with languages APIs, often come test suites to assert compliance. Either the maintainers of the Web Crypto specification or third parties, very likely define/offer a test suite for the specification. If such a test suite exists, we should try to incorporate it in this extension to maximize our compliance and safety.

@codebien pointed out this specific test suite which might be worth investigating as a first step: https://github.com/web-platform-tests/wpt/tree/master/WebCryptoAPI

[oleiade]

Turns out the test suite pointed out in the description is pretty extensive, but was designed to run in a browser. We should therefore somehow either find a way to automatically download, and wrap the test scripts in a way that k6 can interpret, or copy those tests in our repo, and adjust them accordingly.