Consider setting a dedicated signal handler stack to make sandbox stack overflows recoverable

runtime/include/wasm_stack.h
	int rc        = munmap(stack->buffer, stack->capacity + PAGE_SIZE);
	stack->buffer = NULL;
	if (unlikely(rc == -1)) perror("munmap");
}

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@gparmer gparmer yesterday
You have any idea what happens if we set up a signal for SIG_TRAP, then trap out by hitting the guard page here? Normally the signal would execute on the stack....but....

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@bushidocodes bushidocodes 21 hours ago
@gparmer - I would assume the signal handler would panic the process or something. I seem to recall that you can consider signal handlers to use a dedicated stack. Perhaps we should be doing that so a module stack overflow is recoverable?

Start in runtime/include/wasm_stack.h, especially the guard-page stack cleanup shown in the issue, and research how SIG_TRAP handling behaves when execution reaches that guard page. Determine whether a dedicated signal-handler stack is appropriate; the work is done when sandbox stack overflows can be handled recoverably without relying on the exhausted module stack.