* [flutter_tools] simplication of application store logic

* maybe return null

* fix install tests

* Clean up imports

* revert windows test

* remove unused import

The tool observes a large number of unhandled exceptions during the file copy portion of flutter create. it is difficult to tell whether the permission issue is caused by the source/destination, or whether it is due to a bug in dart:io.

To work around this, implement a permission check for both the source and dest files. If either fails, the tool can exit with a more specific message.

If these checks pass, then perform the actual copy. If the copy fails, fallback to manually copying the bytes

* [flutter_tools] add package_config.json to analyze_once_test.dart

* update pinned null safety deps

* run update-packages

* add http dep to devicelab package

* rerun update-packages

Overhaul of flutter drive in order to deliver a better experience, namely:

* flutter run and flutter drive now share more flags, so code paths that were previously only testable on run are now testable on drive.
* Removes web-initialize-platform as this is no longer used
* flutter drive correctly sets up a logger that shows native exceptions, by connecting to the vm service.
* VM service connection now provides access to memory info without launching devtools (only for debug/profile mode)

Web changes

* Passes on the one test in the repo, otherwise the webdriver code has been isolated as much as possible

Additional NNBD related bug fixes:

No longer passes --enable-experiment to the test script. (FYI @blasten ). earlier we might have assumed that the flutter gallery benchmarks would be migrated along side the app and flutter driver, but only the app under test needs to be migrated. The test scripts should never be run with the experiment.

e2c375084 Roll Dart SDK from 1897e02f5b1c to 96369fde1083 (2 revisions) (flutter/engine#22113) (#69002)

* refactor update_icons

* fix trailing space

* address feedback

* Rename to _iconsMirroredWhenRTL

This reverts commit 95909c2a.

* 000bf4b47 Roll Skia from 2d2f82c00aeb to 5c7bb326a7b3 (33 revisions) (flutter/engine#22059)

* ae92dbf4d Roll Fuchsia Linux SDK from lPMs_KwnU... to gqS_DIjN4... (flutter/engine#22057)

* 92cd74e00 Roll Fuchsia Mac SDK from pZ9FgVZTK... to WLxBkBnZa... (flutter/engine#22055)

* e51c710e1 Roll Dart SDK from a3d902d8598e to 9f907e198970 (2 revisions) (flutter/engine#22058)

* 326b202cc Reland fuchsia external view embedder will be shared with platform view (flutter/engine#22008)

* a9a9a2f34 Roll Skia from 5c7bb326a7b3 to 65674e4c2e56 (3 revisions) (flutter/engine#22060)

* 1233fe490 Revert "Revert "Explicitly make the X connection for EGL. (#21831)" (#21851)" (flutter/engine#21871)

* aed8e019b Fixes Edge trigger route change announcement (flutter/engine#21975)

* 6bc70e4a1 Reland: Migration to PlatformDispatcher and multi-window (flutter/engine#21932)

* 5ca5e2614 Add FlEventChannel (flutter/engine#21316)

* 77b005247 Roll Skia from 65674e4c2e56 to 01b05e5b830b (3 revisions) (flutter/engine#22062)

* 3d27fd5b2 Support loading assets from Android dynamic feature modules (flutter/engine#21504)

* 742dfbefa support uri intent launcher in android (flutter/engine#21275)

* cde1e3fca Auto detect mode to determine which rendering backend to use. (flutter/engine#21852)

* 329ccf775 Roll Skia from 01b05e5b830b to 53281c712159 (1 revision) (flutter/engine#22065)

* cde78c162 Add a golden scenario test for fallback font rendering on iOS take 2 (flutter/engine#22033)

* 4f4599b26 Roll Dart SDK from 9f907e198970 to 37ccceacad41 (3 revisions) (flutter/engine#22069)

* f0b10c54b [web] Prevent using DOM nodes for canvas with large number of draws (flutter/engine#22064)

* a86ba5706 Roll Fuchsia Mac SDK from WLxBkBnZa... to zDfaxkqlv... (flutter/engine#22073)

* 645198aa7 Roll Fuchsia Linux SDK from gqS_DIjN4... to vuKxZmSVj... (flutter/engine#22074)

* 0b26570e9 Revert dart rolls (flutter/engine#22078)

* [flutter_tools] null safety mode is used for dill naming

* add bad test case

* [devicelab] mark uncaight exceptions as flaky

* add print error output

* try and fix test