12432 Work around Samsung keyboard issue (cla: yes)

12434 delete golden files; switch to flutter/goldens (cla: yes)

12435 add dart:html, dart:js, and dart:js_util to the copy of the Dart SDK used for analysis (cla: yes)

12436 Roll dart sdk to 69b5681546c68ab85e2ce6d3e7b92ed7d113e7c1. (cla: yes)

12443 Force exit felt tool on sigint, sigterm (cla: yes)

12445 [web] filter test targets; cache host.dart compilation (cla: yes)

12446 Add support for JIT release mode (cla: yes)