Revert the Metal Experiment (#701)

Metal sounded like a good idea to get in the emulator but frankly I
underestimated just how experimental and not ready it was.
From my write up in the Discord:
```
As is, Metal supports only a few games.
The games it does support freeze on first use of not playing them via Vulkan, because shader translation is broken.
So you need to use a dirty hack to not delete all your shaders.
Not to mention it breaks many games via MoltenVK because of changes to the shared GPU code.

Merging Metal seemed like a great idea, because of the few games it does support.
But I don't think it's worth it. Many of the games it breaks via MoltenVK *don't work via Metal*. 
Which effectively makes current Ryubing worse for Mac users than Ryujinx 1.1.1403.

I think what I'm gonna do is revert Metal, and reopen it as a PR. That way, you can still take advantage of the Metal backend as is, but without making other games worse with no solution.
```

For what it's worth, the shader translation part could at least be
"fixed" by always applying a 30ms delay for shader translation to Metal.
That being said, that solution sucks ass.
The MoltenVK regressions are even worse.



I hope this is not a let down to the Mac users. I hope you realize I'm
reverting this because you're actively getting a worse experience with
it in the emulator.

src/Ryujinx.Graphics.Metal/IndexBufferPattern.cs

@@ -1,118 +0,0 @@
-using Ryujinx.Graphics.GAL;
-using System;
-using System.Runtime.InteropServices;
-using System.Runtime.Versioning;
-
-namespace Ryujinx.Graphics.Metal
-{
-    [SupportedOSPlatform("macos")]
-    internal class IndexBufferPattern : IDisposable
-    {
-        public int PrimitiveVertices { get; }
-        public int PrimitiveVerticesOut { get; }
-        public int BaseIndex { get; }
-        public int[] OffsetIndex { get; }
-        public int IndexStride { get; }
-        public bool RepeatStart { get; }
-
-        private readonly MetalRenderer _renderer;
-        private int _currentSize;
-        private BufferHandle _repeatingBuffer;
-
-        public IndexBufferPattern(MetalRenderer renderer,
-            int primitiveVertices,
-            int primitiveVerticesOut,
-            int baseIndex,
-            int[] offsetIndex,
-            int indexStride,
-            bool repeatStart)
-        {
-            PrimitiveVertices = primitiveVertices;
-            PrimitiveVerticesOut = primitiveVerticesOut;
-            BaseIndex = baseIndex;
-            OffsetIndex = offsetIndex;
-            IndexStride = indexStride;
-            RepeatStart = repeatStart;
-
-            _renderer = renderer;
-        }
-
-        public int GetPrimitiveCount(int vertexCount)
-        {
-            return Math.Max(0, (vertexCount - BaseIndex) / IndexStride);
-        }
-
-        public int GetConvertedCount(int indexCount)
-        {
-            int primitiveCount = GetPrimitiveCount(indexCount);
-            return primitiveCount * OffsetIndex.Length;
-        }
-
-        public BufferHandle GetRepeatingBuffer(int vertexCount, out int indexCount)
-        {
-            int primitiveCount = GetPrimitiveCount(vertexCount);
-            indexCount = primitiveCount * PrimitiveVerticesOut;
-
-            int expectedSize = primitiveCount * OffsetIndex.Length;
-
-            if (expectedSize <= _currentSize && _repeatingBuffer != BufferHandle.Null)
-            {
-                return _repeatingBuffer;
-            }
-
-            // Expand the repeating pattern to the number of requested primitives.
-            BufferHandle newBuffer = _renderer.BufferManager.CreateWithHandle(expectedSize * sizeof(int));
-
-            // Copy the old data to the new one.
-            if (_repeatingBuffer != BufferHandle.Null)
-            {
-                _renderer.Pipeline.CopyBuffer(_repeatingBuffer, newBuffer, 0, 0, _currentSize * sizeof(int));
-                _renderer.BufferManager.Delete(_repeatingBuffer);
-            }
-
-            _repeatingBuffer = newBuffer;
-
-            // Add the additional repeats on top.
-            int newPrimitives = primitiveCount;
-            int oldPrimitives = (_currentSize) / OffsetIndex.Length;
-
-            int[] newData;
-
-            newPrimitives -= oldPrimitives;
-            newData = new int[expectedSize - _currentSize];
-
-            int outOffset = 0;
-            int index = oldPrimitives * IndexStride + BaseIndex;
-
-            for (int i = 0; i < newPrimitives; i++)
-            {
-                if (RepeatStart)
-                {
-                    // Used for triangle fan
-                    newData[outOffset++] = 0;
-                }
-
-                for (int j = RepeatStart ? 1 : 0; j < OffsetIndex.Length; j++)
-                {
-                    newData[outOffset++] = index + OffsetIndex[j];
-                }
-
-                index += IndexStride;
-            }
-
-            _renderer.SetBufferData(newBuffer, _currentSize * sizeof(int), MemoryMarshal.Cast<int, byte>(newData));
-            _currentSize = expectedSize;
-
-            return newBuffer;
-        }
-
-        public void Dispose()
-        {
-            if (_repeatingBuffer != BufferHandle.Null)
-            {
-                _renderer.BufferManager.Delete(_repeatingBuffer);
-                _repeatingBuffer = BufferHandle.Null;
-            }
-        }
-    }
-}