CQ. Migrate index tests for name references to text expectations.

Change-Id: Ib5820e5e49242a29899d70b80f6aec90a5679be9
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/507141
Commit-Queue: Konstantin Shcheglov <scheglov@google.com>
Reviewed-by: Johnni Winther <johnniwinther@google.com>

Author: scheglov