Eliminate temporary byte array allocations in the static constructor of IPAddress. (#57397)

Author: teo-tsirpanis

src/libraries/System.Net.Primitives/src/System/Net/IPAddress.cs

@@ -24,11 +24,11 @@ public class IPAddress
 
         internal const uint LoopbackMaskHostOrder = 0xFF000000;
 
-        public static readonly IPAddress IPv6Any = new IPAddress(new byte[] { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }, 0);
-        public static readonly IPAddress IPv6Loopback = new IPAddress(new byte[] { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 }, 0);
-        public static readonly IPAddress IPv6None = new IPAddress(new byte[] { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }, 0);
+        public static readonly IPAddress IPv6Any = new IPAddress((ReadOnlySpan<byte>) new byte[] { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }, 0);
+        public static readonly IPAddress IPv6Loopback = new IPAddress((ReadOnlySpan<byte>) new byte[] { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 }, 0);
+        public static readonly IPAddress IPv6None = IPv6Any;
 
-        private static readonly IPAddress s_loopbackMappedToIPv6 = new IPAddress(new byte[] { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 255, 255, 127, 0, 0, 1 }, 0);
+        private static readonly IPAddress s_loopbackMappedToIPv6 = new IPAddress((ReadOnlySpan<byte>) new byte[] { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 255, 255, 127, 0, 0, 1 }, 0);
 
         /// <summary>
         /// For IPv4 addresses, this field stores the Address.
@@ -644,7 +644,7 @@ public IPAddress MapToIPv4()
 
         private sealed class ReadOnlyIPAddress : IPAddress
         {
-            public ReadOnlyIPAddress(byte[] newAddress) : base(newAddress)
+            public ReadOnlyIPAddress(ReadOnlySpan<byte> newAddress) : base(newAddress)
             { }
         }
     }