support matching test262-harness?

[ljharb]

In other words, I want to provide a bundled JS file (containing all my shims), and then provide a set of globs matching test262 file paths, and then provide a preprocessor that can skip the tests i don't want, so i can then run it in a browser.

(Also, I'd ideally like to be able to run it in older browsers; not sure if that's possible)