Test improvements

These are various improvements to the test infrastructure following the recent rework. They include:

* Using the same node app starting code for the frontend tests that the functional tests use
* Start frontend tests in the same way as functional ones (renaming the file)
* Remove old run_tests.js file
* Run frontend test files as individual files to get better feedback on which file(s) have failed

The last one I'm a bit dubious about with having to separate out the test functions rather than a loop, but it seems the best way to go forward - we shouldn't be adding frontend tests too frequently.