*Replace this paragraph with a description of what this PR is changing or adding, and why. Consider including before/after screenshots.*

*List which issues are fixed by this PR. You must list at least one issue.*
- https://github.com/flutter/flutter/issues/128381

*If you had to change anything in the [flutter/tests] repo, include a link to the migration guide as per the [breaking change policy].*

Fix typo in `integrationDriver()` function

This reverts commit cb378edc.

This reverts commit fa83fefa.

This reverts commit b96c3c22.

* Revert "Revert "NNBD integration_test (#74922)" (#75030)"

This reverts commit 87b04365.

* fix bad merge issues

This reverts commit cca9592f.