On Windows, os.access(path, os.X_OK) always returns True for any existing
file (NTFS has no execute bit; executability is governed by file extension,
not mode bits). So the test_non_executable_engine test — which chmods the
engine to 0o644 and expects 'fail' — could never pass on Windows.
Fixed doctor.py to use a platform-aware check: on Windows, any existing
file is executable; on POSIX, honor the mode bits via os.access(X_OK).
Fixed the test to assert the correct per-platform expectation: 'pass' on
Windows (chmod is a no-op for executability), 'fail' on POSIX.
Co-authored-by: woolcoxm <13604288+woolcoxm@users.noreply.github.com>
woolcoxm