refactor the tests of options

[ringabout]

I planed to work on timotheecour#6 (comment), however #15730 blocks me.

So I could only refactor the tests of options.
I also find a bug:

import options

# change to templates, it works
# closure anonymous functions doesn't work in VM with JS
# Error: cannot evaluate at compile time: procRan
proc main() =
  var procRan = 0
  some(123).map(proc (v: int) = procRan = v)

static: main()

[juancarlospaco]

Looks good 👍