Comment out mismatch output in element_text.dart
Comment out mismatch output in element_text.dart

We have a few failing tests, so we would get output while running
tests.

Change-Id: I236f2a94ce4b893d9b5331020498fdaacd7ccb37
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/256964
Reviewed-by: Brian Wilkerson <1f7641b6b14c52b9163524ab8d9aabff80176f21@google.com>
Commit-Queue: Konstantin Shcheglov <09e4d7516628963212bf4aace2f97603d2b706e4@google.com>

dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk