9867 Fixed error in generated xml Info.plist. (cla: yes)

9873 Add clang version to Info.plist (cla: yes)

9875 Simplify buildtools (cla: yes)

9883 Roll src/third_party/dart 24725a8559..2b3336b51e (108 commits) (cla: yes)

9890 Log dlopen errors only in debug mode (cla: yes)

9893 Removed logic from FlutterAppDelegate into FlutterPluginAppLifeCycleDelegate (cla: yes)

9894 Add the isMultiline semantics flag to values (cla: yes)

9895 Android Embedding PR37: Separated FlutterActivity and FlutterFragment via FlutterActivityAndFragmentDelegate (cla: yes)