PR #10562: Add missing warmup run when autotuning.
PR #10562: Add missing warmup run when autotuning.

Imported from GitHub PR https://github.com/openxla/xla/pull/10562

The `xla/service/gpu:gemm_algorithm_picker_test` test, run on V100, was hitting the delay kernel timeout because of this.
See #9757 for explanation of why the best practice is to execute a warmup run **without the GpuTimer active**.
Copybara import of the project:

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b4ccf2928ee45ec9139db003378095b948bb73d5 by Olli Lupton <olupton@nvidia.com>:

Add missing warmup run when autotuning.

The xla/service/gpu:gemm_algorithm_picker_test test, run on V100, was
hitting the delay kernel timeout because of this.

Merging this change closes #10562

FUTURE_COPYBARA_INTEGRATE_REVIEW=https://github.com/openxla/xla/pull/10562 from olupton:missing-warmup b4ccf2928ee45ec9139db003378095b948bb73d5
