* Put generated kernel files into <build> directory

* USe default value for kernel file

Includes:
* Roll Skia to f802e757646f424b563fdc1f5b5ee3c677659e98 (flutter/engine#4677)

Pull code out of flx.dart:assemble() to make flx.dart:buildAssets
which creates the AssetBundle. This will allow us to create just
this instead of an entire FLX.

* Use engine-built dart sdk

* Download dart-sdk from engine

* Move up deps to fix dart sdk constraint problem

* Update update_dart_sdk.ps1 for Windows

* Fix tests so they pass analysis

* More types for tests

* Roll engine

* Update dart sdk stamp location in flutter.bat

* Add newline

Re-apply "Send nextId in addition to previousId for traversal order (#14676)"

Fixes #14688

* Let the gallery bundle Id ephemerally change to io.flutter.demo.gallery before deploying

* add a comment

Work around xcodebuild's undocumented freeze when -showBuildSettings is used with -allowProvisioning* (#14684)

Adds a ScaffoldGeometry class and ValueNotifier for it.
A scaffold's ScaffoldGeometry notifier is held in the _ScaffoldState, and is passed to _ScaffoldScope.
New ScaffoldGemometry objects are built and published to the notifier.

* Revert "Roll engine to 834d6eb02988e7f2c44eda05cec908378a1a9138 (#14664)"

This reverts commit c19fbe86.
Reason: timeouts while doing hot reload in hot_mode_dev_cycle__preview_dart_2_benchmark.

fixes.

Contains
* Roll Dart to 223eeb2ebe112aaaddca206aab55cd54b4e54391 (https://github.com/flutter/engine/pull/4659)

This is a temporary workaround until we solve #14594.

* Revert "Revert "Reduce xcodebuild noise #2" (#14641)"

This reverts commit 2d47481f.

* Stop scrapping xcodebuild output, get the right build settings

* clone the command params first

* Change the default for pub tracing to false for non-bot runs

* Review feedback: update docs

* Review feedback

This sets things up so that when we next roll a dev build to beta, it updates the docs.
This means that for a while (until we publish a beta) the dev docs will not be updating.

This adds geometric sort ordering back in for semantics nodes that don't have a sort order defined.

With this change, widgets that either have no sort order, or have an equivalent sort order, will be compared geometrically. The comparison is between the two starting corners, so it is TextDirection-aware: parent nodes that are set to have LTR text will compare upper left corners of their children, and upper right when set to RTL.

Also fixed a bug in the Transform widget that didn't mark modified nodes as needing a semantics update.

* Document how to read the dashboard

* address comments

Let Xcode communicate with Apple and create new provisioning profiles and register new devices (#14589)

It seems that setTraversalBefore doesn't work as well as setTraversalAfter for some reason, although I'm using them the same way. Some apps would lock up TalkBack when traversing if setTraversalBefore was set, but not with the equivalent setTraversalAfter.

It's not entirely clear why this is, but I'm going with this to at least get it fixed for apps we know about.

Fixes #14600

Revert "Disable selection of the Android ARM64 target platform based on the attached device" (#14650)

This reverts commit cdb581807cc11030b63d00c04bb2d55fcb3d7ef4.

Dart has been updated in the engine, and this workaround should no longer be necessary.

Fixes https://github.com/flutter/flutter/issues/14646

Dart 2 applies core library patches during the build, so there is only a single
 dart:async library.

Fixes https://github.com/flutter/flutter/issues/14524

Merging to get back to a green tree.

Need to use `typed(any)` instead of `any` in Dart 2.

* Revert "Revert "Reduce noise in xcodebuild stdout (#14586)" (#14605)"

This reverts commit 8e2278bd.

* Specify the build config when cleaning

Some people call me the space cowboy
Some people call me the gangster of love
Some people call me Maurice

Ensures we don't regress #6577 on Windows.

Ensures we don't regress https://github.com/flutter/flutter/issues/6577.