* refine example code in en doc, test=develop, test=document_fix

* update shape to make it meaningful, test=develop, test=document_fix

error message enhancement for py_func op. 

* solve the conflict of ops with the same name. test=develop

API/OP (ConditionalBlock) error message enhancement (#23480)

* Api (fluid.data/layers.data) error message enhancement. test=develop

* API (Switch) error message enhancement. 

* fix bug: dtype of out in api isfinite is set incorrectly. The dtype should be bool. 

* rename op paddle.fluid.matmul to paddle.matmul
* modify original API fluid.layers.matmul,and add new API paddle.matmul

* add support for value tensor support of fill_constant Op

* Add the matmul, elementwise_euqal, elementwise_sum ops to API2.0
* Fix the import meesage in common_ops_import
* Update the test cast for mm

This reverts commit abe3e690.
test=develop

* solve the conflict of ops with the same name. test=develop

* add functional conv

* add test and doc for function convs, test=develop

* update ConvTransposeOp's InferShape and error message, test=develop

* Add unittest for transformer prediction in dygraph_to_static.

* fix bug in fill_constant api. 

* Make transpose support size 0. test=develop

* support tensor array create read write in dygraph
test=develop

* minor fix
test=develop

* support tensor_array_to_tensor
test=develop

* add while loop case and err msg
test=develop

* refine ut
test=develop

* add inplace_abn_op. test=develop

* add fleet pslib pull and push sparse op and push dense op
* test=develop

* expand parameters, test=develop

* support resnet, test=develop

* fix resnet, test=develop

* support duplicable out, test=develop

* support ptb

* fix bugs, test=develop

* support null input, test=develop

* fix bugs, test=develop

* fix batchNorm is_test, test=develop

* refine code, test=develop

* follow comments, test=develop

* follow comments, test=develop

* follow comments, test=develop

* follow comments, test=develop

* Add parameter(learning_rate) in NoamDecay test=develop

* Polish error Info in while_loop test=develop

* sequential reader stage 1, test=develop

* fix ut, test=develop

* fix iterable=False reset bug, add some logs and polish code, test=develop

* inference feed partial data, test=develop

* Turn on keep_order=True for test, test=develop

* enhance ut to test more cases, test=develop

* test commit for reverting

* Revert "test commit for reverting", test=develop

This reverts commit 80aef42e.

* add ut of merged and unmerged results, test=develop

* add more uts for coverages and add en doc of api, test=develop

* follow comments, test=develop

* change note style, test=develop

* support to modify dict and list in while_loop test=develop

* polish code test=develop