This rolls includes the following changes:
be6309690f (HEAD) Analyze pkg/dart2js_tools on the bots.
6f9073bb9d Wait for Analysis Server errors only while waiting for a response.
5d4e85ba3d Allow `x == null` to be a constant value whenever x is const.
7c77ed04f4 Move deobfuscation tools to the SDK repo
666c8c1a89 Fix @visibleForTemplate tests on Windows.
6fc1dd4480 analyzer_plugin no implicit-casts.
29401573d5 Get documentation comments before metadata as well.
3d0a663518 [vm/frontend-server] Fix frontend_server so that it can be tested.
* fix analyzer hint
* use --enable-asserts instead of --checked
9374aa15fc