PR #12845: [XLA:GPU] add workspace rewrite for FP8 gemm
PR #12845: [XLA:GPU] add workspace rewrite for FP8 gemm

Imported from GitHub PR https://github.com/openxla/xla/pull/12845

Add  workspace rewrite for FP8 with amax fusion.
Copybara import of the project:

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a2b7f41caff2924798021d130566379e65984750 by Shawn Wang <shawnw@nvidia.com>:

add workspace rewrite for FP8 gemm

Merging this change closes #12845

FUTURE_COPYBARA_INTEGRATE_REVIEW=https://github.com/openxla/xla/pull/12845 from shawnwang18:shawnw/fix_cublaslt a2b7f41caff2924798021d130566379e65984750
