* fix bn fuse vardesc and add model saver

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* unify save model in test helper

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* fix mkdir on windows

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* remove magic number use bn bias var desc

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* Simplify the compare op for CPU.

* Use asynchronous tensor copy in reshape_op's kernel.

* Optimize while_op for test, avoiding creating variables every time.
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* Enable the cache of kernel type and kernel function.
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* Enable profiling with gperftools.

* Remove flags for testing, and fix the linking error.
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* Delete the codes of ChooseKernel.
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* Fix bug when preparing ExecutorPrepareContext for while_op.

* Fix missing depending on grpc libraries.

* Remove the redundant print.
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* Follow comments.

* Remove the codes related to prepare the ExecutorPrepareContext for while_op.
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* Initialize the elementwise plugin.

* Implement the basic CUDA kernel of elementwise plugin.
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* Refine the tester for MixedRTPredictor.
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* Enable the profiler in TensorRT engine.

* Support the use of combined inference model in TensorRT unittest, and print the shape of feed targets.

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