gh-102598: Remove obsolete optimization from FORMAT_VALUE opcode (#102599)

Author: sobolevn

Python/bytecodes.c

@@ -3026,20 +3026,10 @@ dummy_func(
                 value = result;
             }
 
-            /* If value is a unicode object, and there's no fmt_spec,
-               then we know the result of format(value) is value
-               itself. In that case, skip calling format(). I plan to
-               move this optimization in to PyObject_Format()
-               itself. */
-            if (PyUnicode_CheckExact(value) && fmt_spec == NULL) {
-                /* Do nothing, just transfer ownership to result. */
-                result = value;
-            } else {
-                /* Actually call format(). */
-                result = PyObject_Format(value, fmt_spec);
-                DECREF_INPUTS();
-                ERROR_IF(result == NULL, error);
-            }
+            result = PyObject_Format(value, fmt_spec);
+            Py_DECREF(value);
+            Py_XDECREF(fmt_spec);
+            ERROR_IF(result == NULL, error);
         }
 
         inst(COPY, (bottom, unused[oparg-1] -- bottom, unused[oparg-1], top)) {