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This reverts commit ce7d9b07.

* exhaustive search for cuDNN conv.
* Refine code and add unit testing.
* Clean code
* Fix model load in fluid/inference and unit testing in conv2d
* Follow comments.

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Warning only at first when CUDA CC not matched.

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* feat(platform): lazy initialization of devicecontext in pool

Use std::async(deferer, []{...}) to lazy initialize DeviceContext in Pool

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* Add future includes

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Make all blob info saved in global device context to be thread based.
Meanwhile save thread id in thread local storage in ParallelDo

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Use OO style to rewrite memory allocation.

This reverts commit 1d91a49d.

* some trivial opt

* remove the fix of lod_tensor and shrink_rnn_memory_op

* refine ShrinkRNNMemoryOp

test=develop

This reverts commit 151e169e.