VertexLoaderTest: Add test for skipped texture coordinates

Jimmie Johnson's Anything with an Engine is known to use texture coordinate 7 (and only texture coordinate 7) in some cases. There are a lot of possible edge-cases, so this test brute-forces all combinations with coordinates 0, 1, and 2.

Source/Core/VideoCommon/CPMemory.h

@@ -575,6 +575,102 @@ struct VAT
       return 0;
     }
   }
+  void SetTexElements(size_t idx, TexComponentCount value)
+  {
+    switch (idx)
+    {
+    case 0:
+      g0.Tex0CoordElements = value;
+      return;
+    case 1:
+      g1.Tex1CoordElements = value;
+      return;
+    case 2:
+      g1.Tex2CoordElements = value;
+      return;
+    case 3:
+      g1.Tex3CoordElements = value;
+      return;
+    case 4:
+      g1.Tex4CoordElements = value;
+      return;
+    case 5:
+      g2.Tex5CoordElements = value;
+      return;
+    case 6:
+      g2.Tex6CoordElements = value;
+      return;
+    case 7:
+      g2.Tex7CoordElements = value;
+      return;
+    default:
+      PanicAlertFmt("Invalid tex coord index {}", idx);
+    }
+  }
+  void SetTexFormat(size_t idx, ComponentFormat value)
+  {
+    switch (idx)
+    {
+    case 0:
+      g0.Tex0CoordFormat = value;
+      return;
+    case 1:
+      g1.Tex1CoordFormat = value;
+      return;
+    case 2:
+      g1.Tex2CoordFormat = value;
+      return;
+    case 3:
+      g1.Tex3CoordFormat = value;
+      return;
+    case 4:
+      g1.Tex4CoordFormat = value;
+      return;
+    case 5:
+      g2.Tex5CoordFormat = value;
+      return;
+    case 6:
+      g2.Tex6CoordFormat = value;
+      return;
+    case 7:
+      g2.Tex7CoordFormat = value;
+      return;
+    default:
+      PanicAlertFmt("Invalid tex coord index {}", idx);
+    }
+  }
+  void SetTexFrac(size_t idx, u8 value)
+  {
+    switch (idx)
+    {
+    case 0:
+      g0.Tex0Frac = value;
+      return;
+    case 1:
+      g1.Tex1Frac = value;
+      return;
+    case 2:
+      g1.Tex2Frac = value;
+      return;
+    case 3:
+      g1.Tex3Frac = value;
+      return;
+    case 4:
+      g2.Tex4Frac = value;
+      return;
+    case 5:
+      g2.Tex5Frac = value;
+      return;
+    case 6:
+      g2.Tex6Frac = value;
+      return;
+    case 7:
+      g2.Tex7Frac = value;
+      return;
+    default:
+      PanicAlertFmt("Invalid tex coord index {}", idx);
+    }
+  }
 };
 template <>
 struct fmt::formatter<VAT>