Michael Drake 4b0ebae56a Add a couple of general JS tests.
The primes one prints its execution time:

  NetSurf without -v: 1300ish
             with -v: 5000ish
      Firefox 38.5.0:  300ish
2016-01-23 10:32:26 +00:00
..
2016-01-23 10:32:26 +00:00
2015-07-12 11:24:20 +01:00