message: Don't explode if the e2e test directory exists when crashing
  This is largely expected in local test environments where the developer probably won't remember to clear out the directory themselves.
diff: @@ -93,7 +93,13 @@ async function writeLogs(sessions, dir) {
  for (let i = 0; i < sessions.length; ++i) {
  const session = sessions[i];
  const userLogDir = `${dir}/${session.username}`;
  + try {
  fs.mkdirSync(userLogDir);
  + } catch (e) {
  + // typically this will be EEXIST. If it's something worse, the next few
  + // lines will fail too.
  + console.warn(`non-fatal error creating ${userLogDir} :`, e.message);
  + }
  const consoleLogName = `${userLogDir}/console.log`;
  const networkLogName = `${userLogDir}/network.log`;
  const appHtmlName = `${userLogDir}/app.html`;
  