salieri: Fix missing guest GPU accessor missing on hashes (#1759)

This adds the guest GPU accessor to hashes computation.
As this change all the hashes from the cache, I added some migration
logic.

This is required for #1755.

Ryujinx.Graphics.Gpu/Shader/Cache/Definition/GuestShaderCacheEntry.cs

@@ -31,7 +31,7 @@ namespace Ryujinx.Graphics.Gpu.Shader.Cache.Definition
         /// </summary>
         /// <param name="header">The header of the cached shader entry</param>
         /// <param name="code">The code of this shader</param>
-        private GuestShaderCacheEntry(GuestShaderCacheEntryHeader header, byte[] code)
+        public GuestShaderCacheEntry(GuestShaderCacheEntryHeader header, byte[] code)
         {
             Header = header;
             Code = code;