Enhance the robustness of the bh_hashmap code

[ApsarasX]

wasm-micro-runtime/core/shared/utils/bh_hashmap.c

Lines 123 to 157 in e6a0184

	void *
	bh_hash_map_find(HashMap *map, void *key)
	{
	uint32 index;
	HashMapElem *elem;
	void *value;
	if (!map || !key) {
	LOG_ERROR("HashMap find elem failed: map or key is NULL.\n");
	return NULL;
	}
	if (map->lock) {
	os_mutex_lock(map->lock);
	}
	index = map->hash_func(key) % map->size;
	elem = map->elements[index];
	while (elem) {
	if (map->key_equal_func(elem->key, key)) {
	value = elem->value;
	if (map->lock) {
	os_mutex_unlock(map->lock);
	}
	return value;
	}
	elem = elem->next;
	}
	if (map->lock) {
	os_mutex_unlock(map->lock);
	}
	return NULL;
	}

In the above code, map ->size may be equal to zero, so there may be an exception of divide by zero.

Although all the places where the bh_hash_map_create function is used have a non-zero size, I think it is still necessary to detect the size inside the hashmap in order to enhance the robustness of the code.

[wenyongh]

Hi, thanks for report the issue! I submitted PR #2073 to enhance the code.