Reland: use flutter features for web and desktop

[jonahwilliams]

Description

Reland of #36465 with fixes to analysis

[zanderso]

FYI https://github.com/flutter/flutter/pull/36692/files

[codecov]

Codecov Report

Merging #36699 into master will decrease coverage by 1.09%.
The diff coverage is 72.09%.

@@            Coverage Diff            @@
##           master   #36699     +/-   ##
=========================================
- Coverage   56.01%   54.92%   -1.1%     
=========================================
  Files         188      188             
  Lines       17432    17414     -18     
=========================================
- Hits         9765     9565    -200     
- Misses       7667     7849    +182

Flag	Coverage Δ
#flutter_tool	54.92% <72.09%> (-1.1%)	⬇️

Impacted Files	Coverage Δ
...ackages/flutter_tools/lib/src/commands/unpack.dart	6.93% <ø> (+0.06%)	⬆️
packages/flutter_tools/lib/src/desktop.dart	86.95% <ø> (+8.38%)	⬆️
...kages/flutter_tools/lib/src/commands/assemble.dart	64.86% <ø> (-0.96%)	⬇️
.../flutter_tools/lib/src/commands/build_fuchsia.dart	81.81% <ø> (+68.18%)	⬆️
packages/flutter_tools/lib/src/device.dart	65.06% <ø> (-2.56%)	⬇️
...ackages/flutter_tools/lib/src/commands/create.dart	72.78% <0%> (ø)	⬆️
.../flutter_tools/lib/src/runner/flutter_command.dart	82.35% <0%> (-0.24%)	⬇️
...lutter_tools/lib/src/windows/windows_workflow.dart	100% <100%> (ø)	⬆️
packages/flutter_tools/lib/src/plugins.dart	86.23% <100%> (ø)	⬆️
...es/flutter_tools/lib/src/macos/macos_workflow.dart	100% <100%> (ø)	⬆️
... and 32 more

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[jonahwilliams]

cc @stuartmorgan