[[CHORE]] Reorder parameters of internal function
[[CHORE]] Reorder parameters of internal function

The `expression` function was recently extended to support a second
parameter describing the parsing context. All other internal functions
that accept this value do so via the first parameter. Refactor the
`expression` function to match that pattern.

thomas658/jshint,jshint/jshint,jshint/jshint,thomas658/jshint