1. clean code;
2. change `cl::Kernel` from unique to shared ptr;
3. `reset` `cl::Program` and `clear` `device_info_` in destroyed of CLRuntime;
4. remove clFlush in destroyed of CLRuntime.

* [LITE][OPENCL] fix OpenCL global static resources. test=develop

* Fix Cxx and light api. test=develop

* [LITE][OPENCL] Add ReleaseResource for OpenCL when Predictor dead. test=develop

* fix void for decontrust. test=develop

* fix miscs. test=develop

* fix miscs. test=develop

* fix miscs. test=develop

* fix miscs. test=develop

* [LITE][OPENCL] fix Hang of mobilenetv1_test and kernel test. test=develop

* [LITE][OPENCL] Fix miscs. test is ok. test=develop

[LITE][OPENCL] Fix opencl backend: Free opencl resources; Fix AddKernel/GetKernel, program and all opencl kernels (#3344)

* [DONT MERGE] Fix opencl backend.

* [LITE][OPENCL] Fix kernels overlapped when add/get for kernels of mnasnet/yolonano. test=develop

* remove useless. test=develop

* add all image kernels for Get/Add kernel. test=develop

* add all image kernels for Get/Add kernel. test=develop

* fix buffer kernels of opencl. test=develop

* fix release opencl. test=develop

* [LITE][OPENCL] fix elemul kernel of opencl. test=develop

* fix instanceNorm of opencl. test=develop

* add more info about cl device info. test=develop

* test=devellop

* add cl file into resulted lib test=develop

* test=develop

* test=develop

[LITE][OPENCL] Add relu image2d kernel unit test, Fix conv2d_1x1, relu, layout using new Image2D Layout (#2564)

* add 3 layout for opencl image. test=develop

* add relu image2d test. test=develop