test: Avoid npm install downloading everything

In the presence of a package-lock.json, `npm install` apparently
downloads all packages even when giving explicit ones on the CLI. Avoid
that by removing package-lock.json before.

tests/run-test.sh

@@ -22,6 +22,7 @@ fi
 git clone --depth=1 https://github.com/cockpit-project/bots
 
 # only install a subset to save time/space
+rm package.json package-lock.json  # otherwise the command below installs *everything*, argh
 npm install axe-core chrome-remote-interface sizzle
 
 export TEST_OS="${ID}-${VERSION_ID/./-}"