Ensure single newline at EOF for core files (#11310)

tests/test_common/test_fixture.hpp

@@ -14,7 +14,7 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
- #pragma once
+#pragma once
 
 #include "gtest/gtest.h"
 
@@ -27,4 +27,4 @@ public:
 
     void run_one_scan_loop();
     void idle_for(unsigned ms);
-};
+};