* [Auto Parallel] Improve the c++ dist attr

* [Auto Parallel] Modify test_program.py

* Support custom stream for standalone executor
Co-authored-by: NYulong Ao <aoyulong@baidu.com>

* Support stream overlap for c_allreduce_sum

* Test CI

* Add notes

* Add SingleStreamGuard for BuildOpFuncList

* Add ExecutionConfig and fix last-live-op bug for standalone executor

* Improve code design

* Fix random op depenency and lr_shedule bugs for standalone executor

* Fix CI errors

* Fix CI errors

* Fix CI errors

* Refactor build_op_downstream_map for standalone executor

* Add some comments