[Gpu] Sample 2D array textures with real layers (#471)

Texture arrays were uploaded and viewed as plain 2D images, so every
layer index in a shader resolved to slice 0. The guest-texture gate
also rejected array, 3D and cube descriptor types outright, sending
those resources to the 1x1 black fallback.

UI atlases hit this constantly, since they pack several sheets as array
slices and pick one per vertex. In Demon's Souls the settings menu
bottom bar stretched a mid-atlas crop across itself, and slider thumbs
and button prompts drew the wrong sheet.

The MIMG decoder already had Dimension and IsArray, so
IsArrayedImageBinding makes one rule out of them for the SPIR-V
translator and the Vulkan backend to share. Both have to agree or the
declared image type and the bound view type mismatch. Sample and gather
bindings with an array address now declare an arrayed image and pass
(u, v, slice). AgcExports reads every slice at the per-slice mip-chain
stride and passes the layers packed in one buffer, which uploads as a
2D array image in a single copy region.

Load and store bindings are unchanged. Arrayed bindings that resolve to
a fallback or to a single-layer guest image get a one-layer 2D array
view so the descriptor still matches the shader.

Tested on Demon's Souls (PPSA01342): the bottom bar, slider thumbs and
button prompts draw their correct sheets. 470 tests pass.

src/SharpEmu.Libs/Gpu/GuestGpuTypes.cs

@@ -30,7 +30,9 @@ internal sealed record GuestDrawTexture(
     GuestSampler Sampler = default,
     // Guest CPU write-tracker generation of the memory RgbaPixels was read
     // from; -1 when the range is untracked or the pixels were not read here.
-    long WriteGeneration = -1);
+    long WriteGeneration = -1,
+    bool ArrayedView = false,
+    uint ArrayLayers = 1);
 
 /// <summary>Raw guest sampler descriptor dwords, copied verbatim from guest memory.</summary>
 internal readonly record struct GuestSampler(
@@ -51,7 +53,9 @@ internal readonly record struct TextureContentIdentity(
     uint DstSelect,
     uint TileMode,
     uint Pitch,
-    GuestSampler Sampler);
+    GuestSampler Sampler,
+    bool Arrayed = false,
+    uint ArrayLayers = 1);
 
 internal sealed record GuestMemoryBuffer(
     ulong BaseAddress,