collecting input variables that only shape needed of each subgraph that compiled by CINN in build_cinn_pass, and expose them to memory optimization of framework passes by declaringDECLARE_INPLACE_OP_INFERER in cinn_launch op.

1. add a subdirectory named `cinn` in `paddle/fluid/operators` directory and move releated files into it
2. seperate CinnLaunchContext class from `cinn_launch_op.h` and put it in a  new independent file named `cinn_launch_context.h`, so that it can be included by others clearly.

* Add the `GetFetchNames` method in CinnGraphSymbolization.

* Use unordered_set instead vector as the type of fetch_var_names.

* Reuse the definition of kCompilationKey.

* Use CompileOptions to set fetch_var_ids.

* Update the argument passing of GraphCompiler.Build.

* Fix some bugs in CinnGraphSymbolization::GetFetchIds.

* Fix the null ptr bug in build_cinn_pass.

* Add test for empty&ctrl var.

* Init the functions of CinnCompiler.

* Add the unit test for CinnCompiler.

* Fix some compilation errors.

* Update the UT of cinn_compiler.

* Use Decomposer&OpFusion passes in CinnCompiler::CompileGraph.

* Update some comments.

* Uncomment some includes in build_cinn_pass.cc.

* Use refs instead of ptrs as returned types of FindGraph & Compile in
CinnCompiler.

* Use the merged CinnGraphSymbolization functions in CinnCompiler.

* add feed op and new var for the generated subgraph

* perfect the test script of build_cinn_pass 

* remove useless clear and perfect some annotation

* Add CinnSubgraphSearchPass

* solve CI problem of subgraph order not same

* fix some bug by review advices

* ensure the independently of subgraph, that mean the subgraph should not have link to out-graph

* rename cinn_subgraph_search_pass to build_cinn_pass and delete paddle_to_cinn_pass

* add flag to control wheter append build cinn pass

* remove AppendPass at ParallelExecutorPassBuilder

* rename paddle_to_cinn_pass to build_cinn_pass in build_strategy and close test_run_from_cinn