Fix KeywordFieldBlockLoaderTests (#126146)

muted-tests.yml

@@ -380,15 +380,9 @@ tests:
 - class: org.elasticsearch.search.CCSDuelIT
   method: testTerminateAfter
   issue: https://github.com/elastic/elasticsearch/issues/126085
-- class: org.elasticsearch.index.mapper.blockloader.KeywordFieldBlockLoaderTests
-  method: testBlockLoaderForFieldInObject {preference=Params[syntheticSource=false, preference=DOC_VALUES]}
-  issue: https://github.com/elastic/elasticsearch/issues/126088
 - class: org.elasticsearch.search.sort.GeoDistanceIT
   method: testDistanceSortingWithUnmappedField
   issue: https://github.com/elastic/elasticsearch/issues/126118
-- class: org.elasticsearch.index.mapper.blockloader.KeywordFieldBlockLoaderTests
-  method: testBlockLoader {preference=Params[syntheticSource=false, preference=DOC_VALUES]}
-  issue: https://github.com/elastic/elasticsearch/issues/126121
 - class: org.elasticsearch.search.basic.SearchWithRandomDisconnectsIT
   method: testSearchWithRandomDisconnects
   issue: https://github.com/elastic/elasticsearch/issues/122707

server/src/test/java/org/elasticsearch/index/mapper/blockloader/KeywordFieldBlockLoaderTests.java

@@ -46,7 +46,9 @@ public class KeywordFieldBlockLoaderTests extends BlockLoaderTestCase {
             .filter(Objects::nonNull);
 
         boolean hasDocValues = hasDocValues(fieldMapping, false);
-        boolean useDocValues = params.preference() == MappedFieldType.FieldExtractPreference.NONE || params.syntheticSource();
+        boolean useDocValues = params.preference() == MappedFieldType.FieldExtractPreference.NONE
+            || params.preference() == MappedFieldType.FieldExtractPreference.DOC_VALUES
+            || params.syntheticSource();
         if (hasDocValues && useDocValues) {
             // Sorted and no duplicates
             var resultList = convertValues.andThen(Stream::distinct)