Add filtering capabilities to both the test runner and the test display. This is a very simple implementation,
but it should work when used as expected.
How it works:
- allow adding a plaintext filter in the url querry, in the form of filter=<name>, which only allows tests that contain that word to show. This is *case sensitive* to match QUnits filtering.
- when the results are received from BrowserScope, along with the usual massaging, this patch creates a new list of tests, containing only tests that match the specified filter. Pass percentages are recalculated with the new test arrays, so that the chart looks ok.
- QUnit has a feature that parses the URL querry for the exact same 'filter' parameter. Only matching tests will run. This test is case sensitive.

Filters that do not match any tests will yield invalid results when the tests are run.

Example URL: http://<domain>/support-matrix-submitter/css-blending-support-matrix/submit.html?filter=background