Migrates quic's settingsframe from std::map to quichashmap. There is no particular reason to use an ordered container, and std::map is not a very efficient data structure. Note: this change makes an effort to preserve the existing order of serialized SETTINGS. Many tests fail if SETTINGS order is permuted. PiperOrigin-RevId: 318555812 Change-Id: Ib3829c1013f70462ff90b946282933a59cf479ec