Remove user switch in container due to CI permission issue.

scripts/run-full-tests

@@ -14,6 +14,4 @@ python -m pip install --upgrade pip==19.3.1
 pip install tox==3.14.0
 tox
 apk add --no-cache borgbackup postgresql-client mariadb-client
-working_directory="$PWD"
-adduser --disabled-password tests
-su - tests -c "cd $working_directory && tox --workdir /tmp -e end-to-end"
+tox --workdir /tmp -e end-to-end