Fix test - times can be 0 sometimes (elastic#115260)

muted-tests.yml

@@ -256,9 +256,6 @@ tests:
 - class: org.elasticsearch.xpack.inference.services.cohere.CohereServiceTests
   method: testInfer_StreamRequest_ErrorResponse
   issue: https://github.com/elastic/elasticsearch/issues/114327
-- class: org.elasticsearch.xpack.security.CoreWithSecurityClientYamlTestSuiteIT
-  method: test {yaml=cluster.stats/30_ccs_stats/cross-cluster search stats search}
-  issue: https://github.com/elastic/elasticsearch/issues/114371
 - class: org.elasticsearch.xpack.inference.services.cohere.CohereServiceTests
   method: testInfer_StreamRequest
   issue: https://github.com/elastic/elasticsearch/issues/114385
@@ -311,9 +308,6 @@ tests:
 - class: org.elasticsearch.packaging.test.EnrollmentProcessTests
   method: test20DockerAutoFormCluster
   issue: https://github.com/elastic/elasticsearch/issues/114885
-- class: org.elasticsearch.test.rest.ClientYamlTestSuiteIT
-  method: test {yaml=cluster.stats/30_ccs_stats/cross-cluster search stats search}
-  issue: https://github.com/elastic/elasticsearch/issues/114902
 - class: org.elasticsearch.xpack.inference.DefaultEndPointsIT
   method: testInferDeploysDefaultElser
   issue: https://github.com/elastic/elasticsearch/issues/114913

rest-api-spec/src/yamlRestTest/resources/rest-api-spec/test/cluster.stats/30_ccs_stats.yml

@@ -121,10 +121,10 @@
   - is_true: ccs._search.total
   - is_true: ccs._search.success
   - exists: ccs._search.skipped
-  - is_true: ccs._search.took
-  - is_true: ccs._search.took.max
-  - is_true: ccs._search.took.avg
-  - is_true: ccs._search.took.p90
+  - exists: ccs._search.took
+  - exists: ccs._search.took.max
+  - exists: ccs._search.took.avg
+  - exists: ccs._search.took.p90
   - is_true: ccs._search.took_mrt_true
   - exists: ccs._search.took_mrt_true.max
   - exists: ccs._search.took_mrt_true.avg
@@ -145,7 +145,7 @@
   - gte: {ccs._search.clusters.cluster_two.total: 1}
   - exists: ccs._search.clusters.cluster_one.skipped
   - exists: ccs._search.clusters.cluster_two.skipped
-  - is_true: ccs._search.clusters.cluster_one.took
-  - is_true: ccs._search.clusters.cluster_one.took.max
-  - is_true: ccs._search.clusters.cluster_one.took.avg
-  - is_true: ccs._search.clusters.cluster_one.took.p90
+  - exists: ccs._search.clusters.cluster_one.took
+  - exists: ccs._search.clusters.cluster_one.took.max
+  - exists: ccs._search.clusters.cluster_one.took.avg
+  - exists: ccs._search.clusters.cluster_one.took.p90