Add warning when disable test_fuse_elewise_add_act_pass on Mac

enforce test_parallel_executor_transformer and test_image_classification_resnet to run in serial (#12545)

* get diff for all changes in current branch

* diff with upstream/develop

* let dist test serial

* 1. Remove PYTHON_FLAGS from paddle_build.sh in paddlepaddle/paddle:latest-dev

* 1. Add PYTHON_FLAGS back
2. Change SIGKILL to SIGINT and SIGTERM

* 1. Add setup.py.in back

* 1. add pip install open-cv in Dockerfile to avoid libusb_exit hanging up which is caused by the opencv-python package missing

* 1. Add the && \ to line above

* 1. Remove the notice comment

* 1. implement StopAll in ListenAndServOp
2. make pserver receive the SIGINT and SIGTERM from outside
3. add unittests for listen_and_serv_op in python

* 1. add blocking queue set to record queue
2. aware all blocking queue when exit and exit gracefully

* 1. Remove comment lines from blocking_queue.h
2. Implement SignalHandler and move all global vars and funcs into it

* 1. Make code follows the style check
2. Move the SignalHandler out of the unnamed namespace

* 1. Make yapf happy

* 1. Call Stop() in destructor to release the resource allocated by ListendAndServOp
2. Change exit status to EXIT_SUCCESS after handling the signal from outside
3. Remove the mis-usage of REMOVE_ITEM in unittests

* 1. use DISABLE_COPY_AND_ASSIGN
2. use program once macro only