* fluid clean: remove print/switch from fluid to static

* remove Switch in static.__init__

* fix conflicts.

* replace Switch by case.

* fix piecewise_lr decay.

* fix typo

* fix conflicts.

* fix lr dtype

* keep Switch in paddle.static.nn.control_flow and fix piecewise_lr.

* fix conflicts.

* keep Switch in the fluid.

* fix Switch doc

* fix example in Switch doc

* fix Switch doc.

* fix static/__init__.

* support promote dtype for static amp training

* unify o1 and o2

* update for unittest

* fix op_role

* add use_promote arg

* fix doc

* add promote unittest

* polish unittests

* fix controflow and test

* relocate metri_op.py

* reloacte nn.py

* fix bug

* fix bug

* fix bug

* fix bug

* fix bug

* fix bug

* fix variable->tensor and fix __all__

* fix ctr_metric_bundle and sparse_embedding

* fix bug of function init

* fix bug of importing sparse_embedding and ctr_metric_bundle

* fix bug

* Update __init__.py

* Unify the static amp codes of fp16 and bf16.

* Polish apis and add unittest.

* Add operator stats collecting tools for program.

* Add the check of number of bloat16 operators in unittest.

* Add warning for operator not supported for amp.

* Add testing of BF16 O1 and O2.

* autofix
Co-authored-by: NLiyulingyue <83450930+Liyulingyue@users.noreply.github.com>

* revert changes in python/paddle/distributed/fleet/utils/hybrid_parallel_util.py

* empty commit, trigger ci

* fix test_slice

---------
Co-authored-by: NSigureMo <sigure.qaq@gmail.com>

* update

* update