llama.cpp b12175：修复 CI 硬件并发数检测并发布多平台构建
原标题：b12175
AI 摘要
llama.cpp 发布 b12175 版本，主要修复 CI 测试问题：自托管 CPU runner 是 8 核容器，但 std::thread::hardware_concurrency 报告的是宿主机核数，导致 test-llama-context 的 table 模式按错误线程数建池，在 8-CPU 任务上跑 4 模型 x 8 线程而挂起。为此新增 TEST_ARG_HARDWARE_CONCURRENCY 与 TEST_ARG_PARALLEL_WORKERS 作为自动选择计数的默认值，并在 cpu-x64-high-perf 上设为 8 和 4。同时照例发布覆盖 macOS、Linux、Windows、Android 的多后端预编译包。
正文节选
<details open> tests : override hardware_concurrency in CI (#31797) The self-hosted CPU runners are containers with 8 CPUs, but std::thread::hardware_concurrency reports the cores of the host. The table mode of test-llama-context sizes its pool from that count, so it runs 4 models x 8 threads on an 8-CPU job and hangs. Add TEST_ARG_HARDWARE_CONCURRENCY and TEST_ARG_PARALLEL_WORKERS as the defaults for the auto-selected counts of test-llama-context and of test-backend-ops, and set them to 8 an