Initial tessellation shader support (#2534)

* Initial tessellation shader support

* Nits

* Re-arrange built-in table

* This is not needed anymore

* PR feedback

Ryujinx.Graphics.Shader/TessSpacing.cs

@@ -0,0 +1,22 @@
+namespace Ryujinx.Graphics.Shader
+{
+    public enum TessSpacing
+    {
+        EqualSpacing = 0,
+        FractionalEventSpacing = 1,
+        FractionalOddSpacing = 2
+    }
+
+    static class TessSpacingExtensions
+    {
+        public static string ToGlsl(this TessSpacing spacing)
+        {
+            return spacing switch
+            {
+                TessSpacing.FractionalEventSpacing => "fractional_even_spacing",
+                TessSpacing.FractionalOddSpacing => "fractional_odd_spacing",
+                _ => "equal_spacing"
+            };
+        }
+    }
+}