Ipaddr#native must also coerce @mask_addr

Before it would be left as an IPv6 mask causing `to_range` to fail.

```
>> IPAddr.new("::2").native.to_range
/opt/rubies/3.0.3/lib/ruby/3.0.0/ipaddr.rb:479:in `set': invalid address (IPAddr::InvalidAddressError)
```

lib/ipaddr.rb

@@ -499,6 +499,7 @@ def set(addr, *family)
       if addr < 0 || addr > IN4MASK
         raise InvalidAddressError, "invalid address: #{@addr}"
       end
+      @mask_addr &= IN4MASK
     when Socket::AF_INET6
       if addr < 0 || addr > IN6MASK
         raise InvalidAddressError, "invalid address: #{@addr}"

test/test_ipaddr.rb

@@ -360,6 +360,11 @@ def test_include?
 
   end
 
+  def test_native_coerce_mask_addr
+    assert_equal(IPAddr.new("0.0.0.2/255.255.255.255"), IPAddr.new("::2").native)
+    assert_equal(IPAddr.new("0.0.0.2/255.255.255.255").to_range, IPAddr.new("::2").native.to_range)
+  end
+
   def test_loopback?
     assert_equal(true,  IPAddr.new('127.0.0.1').loopback?)
     assert_equal(true,  IPAddr.new('127.127.1.1').loopback?)