Update Dockerfile

Dockerfile

@@ -31,8 +31,9 @@ run git lfs install --force
 run git clone https://github.com/python/cpython
 run cd cpython && ./configure --enable-optimizations --with-lto --prefix=$HOME/python --with-system-libmpdec=no
 run cd cpython && make
-run cd python && make test
+run cd cpython && make test
 run cd cpython && make install
+run cd cpython && make clean
 run PATH="${PATH:+${PATH}:}$HOME/python"
 
 run python -m pip install --upgrade --no-cache-dir pip