Clean up tests for the existing brace_style options

- Move several tests not involving brace positions out of the brace position testing
  section, and eliminate duplication
- Ensure parallel tests exist for all 3 brace styles
- Add comments to clarify the sections are testing brace positions
- Move copy-pasted, commented out test up to opening brace position tests comment,
  and add note to update tests correctly if the case is ever supported.
javascript tests for brace_style 'none'