* brings in analyzer version (`0.27.4-alpha.14`) corresponding to current Dart SDK (`1.18.0-dev.2.0`).
* updates analysis to use prefered API for embedder URI resolution
* adds trampolines to `State` and `StatelessWidget` to allow for warning-free within-library @protected access (needed since we closed off access to @protected closures from outside subclasses).
* turns off cache dependency tracking for analysis (in DDC this amounted to a 10% speed improvement).
Introduces a new Dart analysis wrapper that works directly with the analyzer API (in favor of shelling out to a separate process).
Some consequences:
* we no longer need to fear parts (simplifying our dart file gathering)
* we can filter by error code (when needed), rather than by error strings
* no more IO scraping
* no need to generate `main()` or to run with `--package-warnings`
* we now specify an analyzer (and linter) version in the pubspec (we’ll want to make sure this doesn’t diverge too far from the analyzer shipped with the SDK but it does give us some room to play with experimental builds)
* no more (re)scanning of error source files (and so no more source cache)
* should generally be a bit simpler and easier to maintain
* runs a bit faster :)
We use a number of non-public APIs in the test package, which makes our
dependency quite fragile. This patch pins a specific, known-good version. We
should update to the lastest version in a follow-up patch.
