Chrome fixes for VS code (#342)

- As suggested by the Chrome docs, always use a tmp dir when passing `--remote-debugging-port`
- Add graceful exit handler for daemon command
  - This ensures that Chrome is properly closed
- Temporary pin build_daemon version to fix integration tests
- Fix concurrent modification issue

Closes https://github.com/dart-lang/webdev/issues/319
Closes https://github.com/dart-lang/webdev/issues/300

This reverts https://github.com/dart-lang/webdev/pull/322 & https://github.com/dart-lang/webdev/pull/316