So that we have a release where both are available without a deprecation warning.

Move tools tests into a general.shard directory in preparation to changing how we shard tools tests (#36108)

* add trailing commas on list/map/parameters

* add trailing commas on Invocation with nb of arg>1

* add commas for widget containing widgets

* add trailing commas if instantiation contains trailing comma

* revert bad change

* enable lint unnecessary_new

* fix tests

* fix tests

* fix tests

All temporary directory start with `flutter_` and have their random component separated from the name by a period, as in `flutter_test_bundle.YFYQMY`.

I've tried to find some of the places where we didn't cleanly delete temporary directories, too. This greatly reduces, though it does not entirely eliminate, the directories we leave behind when running tests, especially `flutter_tools` tests.

While I was at it I standardized on `tempDir` as the variable name for temporary directories, since it was the most common, removing occurrences of `temp` and `tmp`, among others.

Also I factored out some common code that used to catch exceptions that happen on Windows, and made more places use that pattern.

* Upgrade everything except matcher.
* Roll matcher (and test)
* Adjust tests that depend on flutter:test directly to depend on a shim
* Require use of package:test shim and remove other references to package:test

* Add `--dry-run` option to `flutter format` sub command

* Add `--set-exit-if-changed` option to `format` sub command

* Add `--machine` option to `format` sub command

* Make variable names to be not shorthand: cmd -> command

Fix https://github.com/flutter/flutter/pull/18360#discussion_r199656120

* Enforce valid package names on flutter create

Fixes #9564

* refactor

* fix other tests

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.

* Remove the workaround that pinned args to v0.13.6
This reverts most of the changes in commit 6331b6c8
* throw exception if exit code is not an integer
* rework command infrastructure to throw ToolExit when non-zero exitCode
* convert commands to return Future<Null>
* cleanup remaining commands to use throwToolExit for non-zero exit code
* remove isUnusual exception message
* add type annotations for updated args package

Implement flutter format, fixes https://github.com/flutter/flutter/issues/5338

* implement flutter packages get/upgrade command
* alias flutter pub
* refactor findProjectRoot for use by multiple commands

fixes https://github.com/flutter/flutter/issues/4994