Test author (#1)

* fix(aws-sd): service instances registration and deregistration (#5135)

* Only de-register removed targets

* Use maps for current targets lookup.

* Use camelCase, not _

* fix(registry): handle empty targets in TXT records logging an error

* fix(registry): improve logging for TXT records with empty targets and add unit test

* test(registry): enhance logging for empty targets in TXT records test

Author: saikatharryc