Port shared tests folder (#1467)

These tests were presumably once shared with the old integration tests repo
but have since been sat doing nothing. This brings them into the unit tests
project.

Co-authored-by: Wojciech Nagórski <wojtpl2@gmail.com>

src/Renci.SshNet/Abstractions/SocketAbstraction.cs

@@ -292,7 +292,7 @@ public static int Read(Socket socket, byte[] buffer, int offset, int size, TimeS
                 {
                     if (IsErrorResumable(ex.SocketErrorCode))
                     {
-                        ThreadAbstraction.Sleep(30);
+                        Thread.Sleep(30);
                         continue;
                     }
 
@@ -346,7 +346,7 @@ public static void Send(Socket socket, byte[] data, int offset, int size)
                     if (IsErrorResumable(ex.SocketErrorCode))
                     {
                         // socket buffer is probably full, wait and try again
-                        ThreadAbstraction.Sleep(30);
+                        Thread.Sleep(30);
                     }
                     else
                     {

src/Renci.SshNet/Abstractions/ThreadAbstraction.cs

@@ -6,15 +6,6 @@ namespace Renci.SshNet.Abstractions
 {
     internal static class ThreadAbstraction
     {
-        /// <summary>
-        /// Suspends the current thread for the specified number of milliseconds.
-        /// </summary>
-        /// <param name="millisecondsTimeout">The number of milliseconds for which the thread is suspended.</param>
-        public static void Sleep(int millisecondsTimeout)
-        {
-            Thread.Sleep(millisecondsTimeout);
-        }
-
         /// <summary>
         /// Creates and starts a long-running <see cref="Task"/> for the specified <see cref="Action"/>.
         /// </summary>

src/Renci.SshNet/SshMessageFactory.cs

@@ -16,7 +16,7 @@ internal sealed class SshMessageFactory
         private readonly bool[] _activatedMessagesById;
         private readonly object _lock = new object();
 
-        private static readonly MessageMetadata[] AllMessages = new MessageMetadata[]
+        internal static readonly MessageMetadata[] AllMessages = new MessageMetadata[]
             {
                 new MessageMetadata<KeyExchangeInitMessage>(0, "SSH_MSG_KEXINIT", 20),
                 new MessageMetadata<NewKeysMessage>(1, "SSH_MSG_NEWKEYS", 21),
@@ -263,7 +263,7 @@ private static SshException CreateMessageTypeAlreadyEnabledForOtherMessageExcept
                                                  currentEnabledForMessageName));
         }
 
-        private abstract class MessageMetadata
+        internal abstract class MessageMetadata
         {
             protected MessageMetadata(byte id, string name, byte number)
             {