FireFox portable still writes data in the appdata folder

The folders in APPDATA are required while Firefox is running and should be removed on exit. If a specific one isn't in the current release, please file a bug report.

The crash reporter is enabled but writes to FirefoxPortable\Data\profile\CrashReports. It doesn't matter much as Firefox crashes are exceedingly rare these days unless someone is using a blacklisted video driver.