refactor: Remove unnecessary test cases and improve code readability in concurrency_test.py and concurrency_test_bonus.py

refactor: Remove debug print statements and commented out code in executor_insert.h, executor_update.h, and sm_manager.cpp

refactor: Remove commented out code, fix failure handling, and add debug prints for transaction management

refactor: Remove commented out code, fix failure handling, and add debug prints for transaction management

refactor: Improve error handling and fix handling of empty result in Analyze::check_clause and AbstractExecutor::eval_cond