* [xdoctest][task 171-180] reformat example code with google style in audio/*

* [xdoctest][task 171-180] reformat example code with google style in audio/*

* [xdoctest][task 171-180] reformat example code with google style in audio/*

* [xdoctest][task 171-180] reformat example code with google style in audio/*

* [xdoctest][task 171-180] reformat example code with google style in audio/*

* [xdoctest][task 171-180] reformat example code with google style in audio

* [xdoctest][task 171-180] reformat example code with google style in audio/*

* [xdoctest][task 171-180] reformat example code with google style in audio/*

* [xdoctest][task 171-180] reformat example code with google style in audio/*

* [xdoctest][task 171-180] reformat example code with google style in audio/*

* [xdoctest][task 171-180] reformat example code with google style in audio/*

* [xdoctest][task 171-180] reformat example code with google style in audio/*

* [xdoctest][task 171-180] reformat example code with google style in audio/*

* [xdoctest][task 171-180] reformat example code with google style in audio/*

* [xdoctest][task 171-180] reformat example code with google style in audio/*

* [xdoctest][task 171-180] reformat example code with google style in audio/*

* Add outputs to check_numerics_kernel.

* Add check_numerics to yaml.

* Add API and unittest.

* Add check_nan_inf_level as argument of check_numerics_kernel.

* Add more unittests.

* Fix static API implementation and unittest.

* Move the implementation of check_numerics to paddle.amp.

* Fix import error.

* 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.

* [AMP] Add python API for collecting operator stats.

* Fix import and polish codes.

* Add more unittest.

* Add doc for the new APIs.