!!! NOTE to Google3 rollers:
If this change causes test failures in google3 you can temporarily
set `null_safety_asserts = False` on the failing
`dart_browser_binary` targets until we can fix the mistyped code.
That should allow the test to pass with this change.
Of course feel free to revert this change again if the number of
failures is too high.
Re-land previously reverted change:
https://dart-review.googlesource.com/c/sdk/+/258780
Adds additional tests and more checks to ensure assertions are only
added in libraries that have been migrated to null safety.
Issue: https://github.com/dart-lang/sdk/issues/49918
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/259120
Reviewed-by: Sigmund Cherem <sigmund@google.com>
Commit-Queue: Nicholas Shahan <nshahan@google.com>
Change-Id: Idcab0fe49a8dd98cdd73192eabae4439aebe2013
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/260070
