* cherry-pick fix dataloader early reset bug, test=release/1.7

* cherry-pick implementation changing, test=release/1.7

* fix ut, test=release/1.7

test=release/1.7, test=develop

* add learning rate api; test=develop

* fix uni test converage; test=develop

* fix travis ci error; test=develop

* fix comment; test=develop

* fix example error; test=develop

* polish the api description, test=develop
Co-authored-by: Nzhongpu <2013000149@qq.com>
Co-authored-by: Nhong <43953930+phlrain@users.noreply.github.com>

* add parameter check; test=develop

* change parameter name checker in dygraph guard; test=develop

* fix test layers error; test=develop

* revert some code to develop; test=develop

* fix exampel error; test=develop

* fix comment error; test=develop

* fix comment error; test=develop

* cherry-pick #22266

* cherry-pick #22169
test=release/1.7, test=develop

* [cherry-pick] fluid-lite subgraph resnet50 test. test=develop test=release/1.7

* modify lite commit id. test=develop test=release/1.7

* add mul and matmul quantization, test=develop (#22054)
* add test for matmul, test=develop

[cherry-pick] faster build by reduce by-product, reduce linking library and fix compile warning of std=c++11(#22230)

* test=develop, bug fix for sparse recorder

[cherry-pick] #22191
- 添加了fluid-lite子图方式运行resnet的单测
- 修改了依赖Lite的git commit id

* add NotImplementedError for multi optimizers used on multi-places . test=develop

* assert error only if num_devices>1. test=develop

* set test_optimizer_in_control_flow in CMakeLists for using multi-GPU.test=develop

* polish executor hint message, test=develop

* fix punctuation error, test=develop

* test Optimizer in dygraph, test=develop

* add optest for Optimizer in dygraph, test=develop

* fix adagrad optimizer, test=develop

* fix dpsgd optimizer, test=develop

* fix test_optimizer.py, test=develop

* fix dpsgd optimizer, this op only support cpu, test=develop

* add optest for optimizer, test=develop

* add description for dpsgd, test=develop

* add rmsprop to white_list in unused_var_check.cc, test=develop

* polish code style, test=develop

* polish code style, test=develop

* delete seed attribute for DpsgdOptimizer, test=develop

* change testing to debugging, test=develop

* use snake_cased Layer name

* add named_parameters and named_sublayers api

* add include_sublayers param, add unittest
test=develop

* fix named unittests
test=develop

* fix unittest
test=develop

* add api docs
test=develop

* arg fix
test=develop

* reserve rnn_impl name_scope for static graph
test=develop

* fix load static param
test=develop

* fix load static param
test=develop

* add clear_gradients for Optimizer, add api description, test=develop

* fix optest for optimizer's clear_gradient interface, test=develop

* add sample code, test=develop

* polish sample code, test=develop

* update layers, test=develop

* update layers for resnet, test=develop

* fix is_test attr, test=develop

* update cycle_gan, test=develop

* update reinforcement_learning, test=develop

* update ocr, test=develop

* fix bug, test=develop

* Polish the PADDLE_ENFORCE in fusion_group pass related codes.
test=develop

* Correct the unittest because of the change relu_grad's formula.
test=develop

tweak the interface of cache_third_party function - expose the SOURCE_DIR for each external library (#21899)

* update PRelu arg
test=develop

* fix unittests
test=develop

* fix element mode alpha shape
test=develop

* split channel_or_input_shape arg
test=develop

* fix unittest
test=develop

* add support for nested profiling event and printing in different level