DevTools cherry picks for Dart / Flutter stable

[kenzieschmoll]

Fix a bug preventing DevTools extensions from loading for a Dart CLI app (when DevTools is served through DDS)

• 071405a
• 1802328

Fix a bug preventing DevTools extensions to load on Windows

• 2030841
• c086cd6

Updates stable for the new location of the Devtools survey metadata file

• 11d2c86

Fixes a bug where the Flutter SDK was getting cached as a package directory for the inspector

• 5387b11
• 7a8d3eb