Fix Returning Resources with Non-Matching Identifier

[alexanderkiel]

FHIR searches for identifiers like [base]/Patient?identifier=foo can sometimes return non-matching results even in case there is no Patient with the identifier foo at all. However in every case all matching results are returned.

A related issue is #1685. Which only solved the problem in the case that the resource with the matching identifier existed and a second, non-matching resource was returned.

The reason is that the index structure of Blaze uses hashing and hash collisions are not resolved. The issue #2028 will resolve that root cause.