https://github.com/catapult-project/catapult/issues/2447

Right now, when you go to /migrate_test_names, it lists the tests that will be migrated, but not what paths they will be migrated to. This makes it way too easy to incorrectly configure the migration. We should change the UI so that it shows both the test path that will be migrated and the test path it will be migrated to.

Currently, the listTests() function in migrate_test_names.html does an xhr to /list_tests: https://github.com/catapult-project/catapult/blob/master/dashboard/dashboard/templates/migrate_test_names.html#L20

We should implement a simple endpoint in migrate_test_names.py which calls list_tests.GetTestsMatchingPattern() directly and calls _GetNewTestPath() on them to show the new path.

The UI should also be refreshed to fit v2spa.