ES|QL: unmute INLINE STATS generative tests (elastic#136798)

Since elastic#135679 was fixed,
we can re-enable INLINE STATS generative tests.

Unfortunately, there is a new failure, see
elastic#136797, so I had to add
an exception for that (that means `PostOptimizationPhasePlanVerifier`
checks won't be considered by generative tests)

Author: luigidellaquila

x-pack/plugin/esql/qa/server/src/main/java/org/elasticsearch/xpack/esql/qa/rest/generative/GenerativeRestTest.java

@@ -67,11 +67,11 @@ public abstract class GenerativeRestTest extends ESRestTestCase implements Query
         "Data too large", // Circuit breaker exceptions eg. https://github.com/elastic/elasticsearch/issues/130072
         "optimized incorrectly due to missing references", // https://github.com/elastic/elasticsearch/issues/131509
         "long overflow", // https://github.com/elastic/elasticsearch/issues/135759
-        "can't build page out of released blocks", // https://github.com/elastic/elasticsearch/issues/135679
         "cannot be cast to class", // https://github.com/elastic/elasticsearch/issues/133992
         "can't find input for", // https://github.com/elastic/elasticsearch/issues/136596
         "unexpected byte", // https://github.com/elastic/elasticsearch/issues/136598
         "Rule execution limit", // https://github.com/elastic/elasticsearch/issues/136599
+        "Output has changed from", // https://github.com/elastic/elasticsearch/issues/136797
 
         // Awaiting fixes for correctness
         "Expecting at most \\[.*\\] columns, got \\[.*\\]", // https://github.com/elastic/elasticsearch/issues/129561

x-pack/plugin/esql/qa/testFixtures/src/main/java/org/elasticsearch/xpack/esql/generator/EsqlQueryGenerator.java

@@ -17,6 +17,7 @@
 import org.elasticsearch.xpack.esql.generator.command.pipe.EvalGenerator;
 import org.elasticsearch.xpack.esql.generator.command.pipe.ForkGenerator;
 import org.elasticsearch.xpack.esql.generator.command.pipe.GrokGenerator;
+import org.elasticsearch.xpack.esql.generator.command.pipe.InlineStatsGenerator;
 import org.elasticsearch.xpack.esql.generator.command.pipe.KeepGenerator;
 import org.elasticsearch.xpack.esql.generator.command.pipe.LimitGenerator;
 import org.elasticsearch.xpack.esql.generator.command.pipe.LookupJoinGenerator;
@@ -69,8 +70,7 @@ public class EsqlQueryGenerator {
         ForkGenerator.INSTANCE,
         GrokGenerator.INSTANCE,
         KeepGenerator.INSTANCE,
-        // awaits fix for https://github.com/elastic/elasticsearch/issues/135679
-        // InlineStatsGenerator.INSTANCE,
+        InlineStatsGenerator.INSTANCE,
         LimitGenerator.INSTANCE,
         LookupJoinGenerator.INSTANCE,
         MvExpandGenerator.INSTANCE,