It doesn't look like this test has ever worked, and nobody wants to mess with that code. (#133688)

So let's just drop it - if we ever do dare to change the conversion code, we can add
proper tests then.

muted-tests.yml

@@ -471,9 +471,6 @@ tests:
 - class: org.elasticsearch.upgrades.TransformSurvivesUpgradeIT
   method: testTransformRollingUpgrade
   issue: https://github.com/elastic/elasticsearch/issues/132892
-- class: org.elasticsearch.index.mapper.LongFieldMapperTests
-  method: testFetchCoerced
-  issue: https://github.com/elastic/elasticsearch/issues/132893
 - class: org.elasticsearch.xpack.eql.planner.QueryTranslatorTests
   method: testMatchOptimization
   issue: https://github.com/elastic/elasticsearch/issues/132894

server/src/test/java/org/elasticsearch/index/mapper/LongFieldMapperTests.java

@@ -118,10 +118,6 @@ public class LongFieldMapperTests extends WholeNumberFieldMapperTests {
         return randomDoubleBetween(-MAX_SAFE_LONG_FOR_DOUBLE, MAX_SAFE_LONG_FOR_DOUBLE, true);
     }
 
-    public void testFetchCoerced() throws IOException {
-        assertFetch(randomFetchTestMapper(), "field", 3.783147882954537E18, randomFetchTestFormat());
-    }
-
     protected IngestScriptSupport ingestScriptSupport() {
         return new IngestScriptSupport() {
             @Override