Created by: yihuaxu

Fix ISSUE#14883 and add the unit testing for conv2d.

Command: FLAGS_use_mkldnn=true FLAGS_paddle_num_threads=20 KMP_AFFINITY=compact,granularity=fine ./paddle/fluid/inference/tests/api/test_analyzer_resnet50 --infer_model=third_party/inference_demo/mobilenet_depthwise_conv/model --repeat=100 --gtest_filter=Analyzer_resnet50.profile_mkldnn --batch_size=1 --num_threads=1 --profile --paddle_num_threads=28