test_runner: expose location of tests
This commit adds each test's line and column number to the reporter output. This will aid in debugging test suite failures when error stacks are not helpful, test suites are large, or tests have the same name. This data is also exposed on the spec reporter.
This commit also replaces the filename that was previously being reported, with the filename where the test actually exists. These are normally correct, but could be wrong if tests were run from a file other than the user's entrypoint.