WL#12367: MTR: Generate a report of number of queries run on secondary

          engine

Post-push fix: Fix new Clang build warnings.

Change-Id: I658bda946e9a632167f5beb6e248bffbd568dc9d

Author: jhauglid

client/mysqltest/secondary_engine.h

@@ -31,10 +31,10 @@ typedef std::vector<unsigned int> Errors;
 
 class Secondary_engine {
  public:
-  Secondary_engine(){};
+  Secondary_engine() {}
   Secondary_engine(bool change_propagation);
 
-  ~Secondary_engine(){};
+  ~Secondary_engine() {}
 
   /// Get the secondary engine execution count value.
   ///