run-tests: also follow symlink when update PATH with 'run-tests.py' dir I'm using 'run-tests.py' from my '$PATH' and use a symlink to get 'run-tests.py' to in that '$PATH'. There is a handful of test helpers (like f) that needs to be in the '$PATH' for the test to run, and they are expected to live next to the 'run-tests.py' binary. Using a symlink confuses this logic, so we add to the '$PATH' both the 'run-tests.py' executable directory, and the actual file location direction.