Merge "Avoid thread cache in unwinder." into sc-dev

    // TODO: Create this once and store it in a global?

    unwindstack::UnwinderFromPid unwinder(kMaxFrames, getpid());

    // Do not use the thread cache here because it will call pthread_key_create

    // which doesn't work in linker code. See b/189803009.

    // Use a normal cached object because the process is stopped, and there

    // is no chance of data changing between reads.

    auto process_memory = unwindstack::Memory::CreateProcessMemoryCached(getpid());

    unwinder.SetProcessMemory(process_memory);

    dump_backtrace_thread(output_fd, &unwinder, thread);

  }

  __linker_disable_fallback_allocator();