PR #11241: [XLA:CPU] Enable BMM+Mul+Add for bf16
PR #11241: [XLA:CPU] Enable BMM+Mul+Add for bf16

Imported from GitHub PR https://github.com/openxla/xla/pull/11241

This PR enable BatchMatmul + Mul + Add fusion for BF16 and also fixes a bug for the same.
Copybara import of the project:

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abdbf9b89925c8553296122c846327b6dffa86ce by Kanvi Khanna <kanvi.khanna@intel.com>:

Enable BMM+Mul+Add for bf16

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6674ac76b868f0399731d6185287eec76244df3a by Kanvi Khanna <kanvi.khanna@intel.com>:

fix test

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8fb80082e8c545e007ab7a2d363eb7b7c251fd07 by Kanvi Khanna <kanvi.khanna@intel.com>:

address review comment, fix test, format

Merging this change closes #11241

FUTURE_COPYBARA_INTEGRATE_REVIEW=https://github.com/openxla/xla/pull/11241 from Intel-tensorflow:kanvi/bmm-mul-add_bf16 8fb80082e8c545e007ab7a2d363eb7b7c251fd07
