Test runner file matcher should walk as little as possible

[nayeemrmn]

If I run deno -A https://deno.land/std/testing/runner.ts projects/deno_std/fmt/sprintf_test.ts, it walks the whole directory tree from CWD and takes a really long time. Obviously no walking should be done in this case - sound easy enough.

Ideally though, deno test projects/deno_std/fmt/*_test.ts would only walk projects/deno_std/fmt. At that point you'd want to extract a magical glob expansion utility in //fs.

[bartlomieju]

Yeah it makes sense. I'll update the test runner

[bartlomieju]

I got caught up in other work, if someone wants to tackle that feel free