framehop: remove the allocation in signal handle of framehop

[YangKeao]

close #281

1. Initialize the FramehopUnwinder before the first call to the perf_signal_handler.
2. Add a test to make sure the signal handler doesn't have memory allocation.
3. Modify the github action to run related tests for framehop. I believe framehop will be a better choice (than backtrace-rs) in the future.
4. Modify the code to use spin::RwLock instead of the static mut, though there is no safety issue actually.