Fix issues with CMake 4 dropping compatibility for old versions. This is causing CI failures (see https://github.com/pytorch/cpuinfo/actions/runs/19111787654/job/54633008879).

• Update googletest to 1.17 (from 1.11) and googlebenchmark to 1.9.4 (from 1.6.1).
  • CMake 4.x complains about the CMake 3.5 minimum version used in dependencies.
• Bump the minimum CMake version in DownloadGoogleTest/Benchmark CMake files (it complains).

I also ran into a naming conflict in the benchmarks with the benchmark functions shadowing the cpuinfo functions they call. I'm not entirely sure why this is a problem after the dependency update, but I've added a _bench suffix, which resolves the issue.