First pass at converting number tests

I converted all tests that had any actual code in them with one exception:
the `parse_icu4j3_6` was a swiss cheese of comments so I should confirm its
even valid before teasing it all apart.

I fixed up styling in most places, though there's still some places where
it's a bit too condensed. I left the commented out tests in place, and
converted them too.

There's one test in number.parse that's failing, but it should be failing in
doh too.