MLT Query: Fix exclude with artificial documents

Artificial documents get assigned a random id. When include is set to false
(default), the ids of these documents also get included, when they should
rather be ignored.

Closes #8679
[TEST] Use different index on each iteration to ensure less timeout prone tests
Test: add trace logging to RelocationTests

also improved error message when failing to delete a dummy doc
[TEST] Add an assert for null indices in InternalEngineIntegrationTest
[TEST] remove outdated TestLogging annotation

Conflicts:
	src/test/java/org/elasticsearch/bwcompat/UnicastBackwardsCompatibilityTest.java
	src/test/java/org/elasticsearch/recovery/RelocationTests.java
[TEST] move test to a different class that can disable publish timeout on demand
[TEST] add back accidetially removed test logging
[TEST] With pipelining disabled requests can come back in any order

Closes #8697
function_score: match only document with score above custom score threshold

functon_score matched each document regardless of the computed score.
This commit adds a query parameter `min_score` (-Float.MAX_VALUE default).
Documents that have a score lower than this threshold will not be mached.

closes #6952