build: improve reliability of find_python.cmd script
The path of the Python executable might contain white spaces. Handle
this when the `check-python` function is called.
Fixes: https://github.com/nodejs/node/issues/42801
PR-URL: https://github.com/nodejs/node/pull/42810
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
