Fix google-app-engine

Add "_python_runtime.py" to the file list.

If this file is omitted then google app engine can't run in development mode and raise the following error:
/usr/bin/python: can't open file '/usr/local/bin/_python_runtime.py': [Errno 2] No such file or directory

Closes #19139.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>