Also, add tests to verify that our coverage is actually being tested!

https://github.com/flutter/flutter/issues/10688

https://github.com/flutter/flutter/issues/10688

* Bump to Dart SDK 1.24.0-dev.6.7.

* nits and fixes

VERSION: 0.0.7-dev
flutter: 0.0.27-dev
flutter_driver: 0.0.5-dev
flutter_test: 0.0.5-dev

VERSION: 0.0.6
flutter: 0.0.26
flutter_driver: 0.0.4
flutter_test: 0.0.4

* Rev versions for alpha branch

* Rev versions after alpha

And add a script to rev the versions.

There are more places we can use this annotation, but this patch just gets us
started.

This adds support for a `--bug-report` flag, which is a recording
that:
  - includes the arguments that were passed to the command runner
  - is zipped up for easy attachment in Guthub issues

* Bump to test `0.12.20`.

Some test `0.12.20` highlights:
  * introduces `expectLater()`  that returns a `Future` that completes when the matcher has finished running
  * deprecates the `verbose` parameter to `expect()` and the `formatFailure()` (to be removed in `0.13.0`)

Otherwise:
  * to keep up w/ the deprecation of `verbose`, removes `widget_tester` API to pass `verbose` flag (alternatively we could suppress the warning for now)

* Update stack manipulation.

* Fix framecount.

* ups pinned `test` to `0.12.15+9` (to play nice w/ the latest analyzer)
* integrates `analyzer` with analysis driver defaulting to ON

This removes direct file access from within flutter_tools
in favor of using `package:file` via a `FileSystem` that's
accessed via the `ApplicationContext`.

This lays the groundwork for us to be able to easily swap
out the underlying file system when running Flutter tools,
which will be used to provide a record/replay file system,
analogous to what we have for process invocations.