* cputime optimize for arm64
Update src/butil/time.cpp
modify using __attribute__((constructor)) and merge init_invariant_cpu_freq to inside function read_invariant_cpu_frequency
* Add the macro switch BUTIL_USE_CPU_FREQUENCY while preserving the original default behavior for ARM64
* 1、Activation options: CMake -DWITH_CPU_FREQUENCY=ON, Bazel --define BUTIL_USE_CPU_FREQUENCY=true, script argument --with-cpu-frequency.
2、Disabled by default for consistent legacy behavior.
* fix compile failed
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Co-authored-by: seekdwh <dongweihao@huawei.com>