* Fix scale kernel for low precision, cherry pick #50998.

* Fix the FP16 precision problem of add_n. (#50129)

* Change squared_l2_norm to reuse ReduceKernel, and register fp16 and bf16 kernel, which is cherry pick #48315.

* Cherry-pick the fix of MPTypeTrait in KP, which is implemented in #50993.

* Cherry-pick the multi-precision support of AdamW for bf16, #48041.

* Fix compiling error.

* Cherry-pick the fix of CubTensorReduceImpl for bfloat16 in #50993.

* Fix unittest.

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Co-authored-by: Nliuruyan <44316842+liuruyan@users.noreply.github.com>