Remove unnecessary include that was breaking test

Author: MichaelRFairhurst

cpp/cert/test/rules/OOP54-CPP/GracefullyHandleSelfCopyAssignment.expected

@@ -1,2 +1,2 @@
-| test.cpp:57:6:57:14 | operator= | User defined copy or user defined move does not handle self-assignment correctly.  |
-| test.cpp:66:6:66:14 | operator= | User defined copy or user defined move does not handle self-assignment correctly.  |
+| test.cpp:56:6:56:14 | operator= | User defined copy or user defined move does not handle self-assignment correctly.  |
+| test.cpp:65:6:65:14 | operator= | User defined copy or user defined move does not handle self-assignment correctly.  |

cpp/cert/test/rules/OOP54-CPP/test.cpp

@@ -1,6 +1,5 @@
 #include <functional>
 #include <string>
-#include <utility>
 
 class A {
 public: