PR #10536: Size 1 Dimensions in Layer Norm Fusion
PR #10536: Size 1 Dimensions in Layer Norm Fusion

Imported from GitHub PR https://github.com/openxla/xla/pull/10536

Enables the fusion of layer norm patterns with degenerate input dimensions of size 1 and with additional optional type conversions or reshapes adding or removing degenerate dimensions.
Copybara import of the project:

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54e247d2bf7104358549f0fc31019c36cfb5ce9b by Philipp Hack <phack@nvidia.com>:

Layer norm fusion for inputs with degenerate dimensions.

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7d766bf95049e0ea7fba30c7b6262dac553c94ed by Philipp Hack <phack@nvidia.com>:

Layer norm fusion for inputs with degenerate dimensions.

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14075f1714dcfec83efe13b8903a34caa4b39c01 by Philipp Hack <phack@nvidia.com>:

Layer norm fusion for inputs with degenerate dimensions.

Merging this change closes #10536

FUTURE_COPYBARA_INTEGRATE_REVIEW=https://github.com/openxla/xla/pull/10536 from philipphack:u_layer_size1_xla 14075f1714dcfec83efe13b8903a34caa4b39c01
