Check that no files are in the test output folder.
Check that no files are in the test output folder.

If there are files, delete them. This ensures the test
runs through the running of a QM job, and doesn't load a
`.thermo` file  (this is tested elsewhere) from a previous test.

chatelak/RMG-Py,enochd/RMG-Py,comocheng/RMG-Py,KEHANG/RMG-Py,nickvandewiele/RMG-Py,chatelak/RMG-Py,nyee/RMG-Py,comocheng/RMG-Py,nickvandewiele/RMG-Py,pierrelb/RMG-Py,pierrelb/RMG-Py,enochd/RMG-Py,KEHANG/RMG-Py,nyee/RMG-Py,faribas/RMG-Py,faribas/RMG-Py