[element model] migrate error_verifier (more checks)

Change-Id: I233e23bf31928f986180b32726f028edd146ea87
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/409861
Commit-Queue: Phil Quitslund <[email protected]>
Reviewed-by: Konstantin Shcheglov <[email protected]>
Reviewed-by: Brian Wilkerson <[email protected]>

Author: pq