Support power-assert as official

[petamoriken]

In Node.js, power-assert is often used to display test results in an easy-to-read format.

  1) Array #indexOf() should return index when the value is present:
     AssertionError: # path/to/test/mocha_node.js:10

  assert(ary.indexOf(zero) === two)
         |   |       |     |   |
         |   |       |     |   2
         |   -1      0     false
         [1,2,3]

  [number] two
  => 2
  [number] ary.indexOf(zero)
  => -1

Deno also has a third party implementation in userland, but it requires AST parsing and is not easy to use. I think it would be useful if Deno provides an official command options to convert the test results.