* [Bugfix][OpenCL] fix depthwise_conv2d_3x3 with dilation > 1. test=develop

* [lite][opencl] remove event with clfinish, add strict check for cl warning. add conv 3x3opt fallback opt layout cast ,test=develop

* [LITE][OPENCL]rm event in element_add_buffer_compute test=develop

* [LITE][OPENCL]suite cl_functions_test.cc test=develop

* [LITE][OPENCL] suite cl_common.sh lint check test=develop

* [LITE][OPENCL] suite conv_image_compute.cc lint check test=develop

* [LITE][OPENCL] suite cl_wait_list() lint check test=develop

* [Lite][OpenCL]fix depthwise_conv3*3 test. test=develop

* [Lite][OpenCL]fix depthwise_conv3*3 test, format codestyle. test=develop

[LITE][OPENCL] support fp16 for cl_image_converter, layout, activation all OpenCL image kernel. test=develop (#2964)

* [LITE][OPENCL] support fp16 for cl_image_converter, layout, activation image kernel. test=develop

* add conv, depthwise and UT. test=develop

* add pool, conv, nearest_interp kernel. test=develop

* support fp16 for scale, reshape, concat, fc buffer opencl kernel. test=develop

* refactor for mul opencl buffer kernel. test=develop

* support fp16 for elementwise_mul opecl image kernel. test=develop

* support fp16 for elementwise_mul opencl image kernel. test=develop

* support fp16 for ele_add, fuse_ele_add_act opencl kernel. test=develop

* rename io_copy. test=develop

* mobilenetv1,v2 passed on 855. test=develop

* fix opt for opencl. test=develop

* comment All opencl buffer kernels. test=develop

* refactor conv, depthwise into one routing selection. test=develop

* [LITE][OPENCL]develop basic image depthwiseconv,passed loop test,test=develop

* [LITE][OPENCL]log to vlog(4),test=develop

* [LITE][OPENCL]fix depthwise buffer conv kernel name ,test=develop