Rewrite shader decoding stage (#2698)

* Rewrite shader decoding stage

* Fix P2R constant buffer encoding

* Fix PSET/PSETP

* PR feedback

* Log unimplemented shader instructions

* Implement NOP

* Remove using

* PR feedback

Ryujinx.Graphics.Shader/IGpuAccessor.cs

@@ -1,4 +1,6 @@
-namespace Ryujinx.Graphics.Shader
+using System;
+
+namespace Ryujinx.Graphics.Shader
 {
     public interface IGpuAccessor
     {
@@ -12,12 +14,7 @@
             return 0;
         }
 
-        T MemoryRead<T>(ulong address) where T : unmanaged;
-
-        bool MemoryMapped(ulong address)
-        {
-            return true;
-        }
+        ReadOnlySpan<ulong> GetCode(ulong address, int minimumSize);
 
         int QueryComputeLocalSizeX()
         {