Fix scheduler fairness test

src/Common/Scheduler/Nodes/tests/ResourceTest.h

@@ -282,7 +282,7 @@ struct ResourceTestManager : public ResourceTestBase
         return link_data[link];
     }
 
-    // Use at least two threads for each queue to avoid queue being deactivated:
+    // Use exactly two threads for each queue to avoid queue being deactivated (happens with 1 thread) and reordering (happens with >2 threads):
     // while the first request is executing, the second request is in queue - holding it active.
     // use onEnqueue() and onExecute() functions for this purpose.
     void onEnqueue(ResourceLink link)

src/Common/Scheduler/Nodes/tests/gtest_dynamic_resource_manager.cpp

@@ -56,7 +56,7 @@ TEST(SchedulerDynamicResourceManager, Fairness)
         EXPECT_NEAR(cur_unfairness, 0, 1);
     };
 
-    constexpr size_t threads_per_queue = 3;
+    constexpr size_t threads_per_queue = 2;
     int requests_per_thread = 100;
     ResourceTest t(2 * threads_per_queue + 1);