Implement Regular Expression split and update Text.split to the new API

[GregoryTravis]

Pull Request Description

Re-implement split on top of Truffle regex.

Checklist

Please ensure that the following checklist has been satisfied before submitting the PR:

• The documentation has been updated, if necessary.
• Screenshots/screencasts have been attached, if there are any visual changes. For interactive or animated visual changes, a screencast is preferred.
• All code follows the
  Scala,
  Java,
  and
  Rust
  style guides. In case you are using a language not listed above, follow the Rust style guide.
• All code has been tested:
  • Unit tests have been written where possible.
  • If GUI codebase was changed, the GUI was tested when built using ./run ide build.

[jdunkerley]

Generally LGTM

[radeusgd]

Looks good to me.

Some comments need aligning, and I suggested a few more tests to add.

I'm wondering if a limit argument wouldn't be better than only_first, as it allows for more flexibility. I think it could be useful, and shouldn't make the implementation more complex. But that's a discussion closer to design, so I'm fine with dealing with this at a different time.