[CodeStyle] use np.testing.assert_array_equal instead of self.assertTrue(np.array_equal(...)) (#44947)

* automatically fix

* update comments

* numpy -> np

* self.assertEqual(..., True)

* wrong usage (err_msg=True)

这不是修复导致的错误，这些是原来 `self.assertTrue(..., True)`
的错误用法，因此在修复后将其认为位置参数 `err_msg`

* some missing fix

* change fluid.mean to paddle.mean

* reverse some old code examples

* use yapf to format all python file

* yapf exclude two unittests file for they rely on writing and reading file, and format will break them

* disable diff_py_file because too many diff files cause command following failed

* fix init_gflags with 'python -c', test=develop

* fix pruned_program_cache_key of Operator, test=develop

* polish api program error message, test=develop

* fix condition error, test=develop

* fix test prune error, test=develop

* fix coverage problem, test=develop

* prune train program by fetch_list, test=develop

* add unittest for prune, test=develop

* fix pruned feed, test=develop

* support ParallelExecutor and feed prune, test=develop

* add comments, test=develop

* update unittest, test=develop

* update unittests, test=develop

* remove debug code, test=develop

* support cond in clone, test=develop

* support cond in prune, test=develop

* support multiple minimize, test=develop

* support cache, test=develop

* fix _copy_param_info_from, test=develop

* support python2 str, test=develop

* remove debug code, test=develop

* fix bug of caching CompiledProgram, test=develop

* fix multi_device issue, test=develop

* tmp

* support tuple in fetch_list and overriding use_prune, test=develop

* dont use nonlocal in python2, test=develop

* remove nonlocal, test=develop

* code clean, test=develop

* code clean, test=develop

* feed list, test=develop

* test adam, test=develop

* follow comments, test=develop

* reduce duplicate code, test=develop

* update comments, test=develop

* add a default value for _prune interface

* modify document