- Move cpu_detect to absl::base_internal, adding the kNvidiaGrace and kIntelGraniterapids enums.
- On aarch64 Linux, implement custom ISAR0.RNDR checking logic to distinguish kArmNeoverseV2 from kNvidiaGrace.
- Add IsSMTEnabled and NumContextsPerCPU
PiperOrigin-RevId: 922862384
Change-Id: I038b7732714400d6c63ff309bf20af3f436afcf5