Update CMakeLists.txt

Remove diagnostic - no longer needed

Author: tadeja

cpp/src/arrow/dataset/CMakeLists.txt

@@ -181,17 +181,6 @@ add_arrow_dataset_test(scanner_test)
 add_arrow_dataset_test(subtree_test)
 add_arrow_dataset_test(write_node_test)
 
-# Diagnostic for issue GH-49958: build two tests as C++23 with libstdc++ backend
-# so the terminate handler prints stack
-if(MINGW
-   AND CMAKE_CXX_COMPILER_ID STREQUAL "GNU"
-   AND CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 14)
-  set_target_properties(arrow-dataset-dataset-writer-test arrow-dataset-file-test
-                        PROPERTIES CXX_STANDARD 23)
-  target_link_libraries(arrow-dataset-dataset-writer-test PRIVATE stdc++exp)
-  target_link_libraries(arrow-dataset-file-test PRIVATE stdc++exp)
-endif()
-
 if(ARROW_CSV)
   add_arrow_dataset_test(file_csv_test)
 endif()