04896c7f90
This CL adds support for strict mode, but disables it in tests and allowed packages. Change-Id: I834bc5a0e88868b282c3901361f7a90e1f9eeb3d Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/289621 Reviewed-by: Johnni Winther <johnniwinther@google.com> Reviewed-by: Srujan Gaddam <srujzs@google.com> Commit-Queue: Joshua Litt <joshualitt@google.com>