Improve reproducability of RestControllerTests

With this commit we use the classic parent circuit breaker which does
not account for real memory usage. In those tests we want to have
reproducible results and hence it makes sense to disable the real memory
circuit breaker there.

server/src/test/java/org/elasticsearch/rest/RestControllerTests.java

@@ -81,6 +81,8 @@ public class RestControllerTests extends ESTestCase {
         circuitBreakerService = new HierarchyCircuitBreakerService(
             Settings.builder()
                 .put(HierarchyCircuitBreakerService.IN_FLIGHT_REQUESTS_CIRCUIT_BREAKER_LIMIT_SETTING.getKey(), BREAKER_LIMIT)
+                // We want to have reproducible results in this test, hence we disable real memory usage accounting
+                .put(HierarchyCircuitBreakerService.USE_REAL_MEMORY_USAGE_SETTING.getKey(), false)
                 .build(),
             new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS));
         usageService = new UsageService(settings);