PR #11881: Improve NVTX ranges emitted during auto-tuning
PR #11881: Improve NVTX ranges emitted during auto-tuning

Imported from GitHub PR https://github.com/openxla/xla/pull/11881

New ranges:
 - XlaAutotunerCompilation
 - XlaAutotunerMeasurement

Allow easier analysis of which parts of autotuning are related to compilation.
Copybara import of the project:

--
921c3c39c3cc919f360ef8c6bb9828d96fb0cf49 by Olli Lupton <olupton@nvidia.com>:

Improve NVTX ranges emitted during auto-tuning

New ranges:
 - XlaAutotunerCompilation
 - XlaAutotunerMeasurement

Merging this change closes #11881

FUTURE_COPYBARA_INTEGRATE_REVIEW=https://github.com/openxla/xla/pull/11881 from olupton:autotuner-annotations 921c3c39c3cc919f360ef8c6bb9828d96fb0cf49
