Fixed unnecessary zero-length array allocations

Changed all currently present zero-length array allocations in the codebase to use `Array.Empty` instead.

OpenRA.Mods.Cnc/Graphics/TeslaZapRenderable.cs

@@ -58,7 +58,7 @@ namespace OpenRA.Mods.Cnc.Graphics
 
 			cachedPos = WPos.Zero;
 			cachedLength = WVec.Zero;
-			cache = new IFinalizedRenderable[] { };
+			cache = Array.Empty<IFinalizedRenderable>();
 		}
 
 		public WPos Pos => pos;

OpenRA.Mods.Cnc/SpriteLoaders/TmpRALoader.cs

@@ -9,6 +9,7 @@
  */
 #endregion
 
+using System;
 using System.IO;
 using OpenRA.Graphics;
 using OpenRA.Primitives;
@@ -32,7 +33,7 @@ namespace OpenRA.Mods.Cnc.SpriteLoaders
 				Data = data;
 
 				if (data == null)
-					Data = new byte[0];
+					Data = Array.Empty<byte>();
 				else
 					Size = size;
 			}

OpenRA.Mods.Cnc/SpriteLoaders/TmpTDLoader.cs

@@ -9,6 +9,7 @@
  */
 #endregion
 
+using System;
 using System.IO;
 using OpenRA.Graphics;
 using OpenRA.Primitives;
@@ -32,7 +33,7 @@ namespace OpenRA.Mods.Cnc.SpriteLoaders
 				Data = data;
 
 				if (data == null)
-					Data = new byte[0];
+					Data = Array.Empty<byte>();
 				else
 					Size = size;
 			}

OpenRA.Mods.Cnc/SpriteLoaders/TmpTSLoader.cs

@@ -9,6 +9,7 @@
  */
 #endregion
 
+using System;
 using System.IO;
 using OpenRA.Graphics;
 using OpenRA.Primitives;
@@ -109,7 +110,7 @@ namespace OpenRA.Mods.Cnc.SpriteLoaders
 					}
 				}
 				else
-					Data = new byte[0];
+					Data = Array.Empty<byte>();
 			}
 		}
 

OpenRA.Mods.Cnc/UtilityCommands/RemapShpCommand.cs

@@ -50,7 +50,7 @@ namespace OpenRA.Mods.Cnc.UtilityCommands
 			Game.ModData = destModData;
 			var destPaletteInfo = destModData.DefaultRules.Actors[SystemActors.Player].TraitInfo<PlayerColorPaletteInfo>();
 			var destRemapIndex = destPaletteInfo.RemapIndex;
-			var shadowIndex = new int[] { };
+			var shadowIndex = Array.Empty<int>();
 
 			// the remap range is always 16 entries, but their location and order changes
 			for (var i = 0; i < 16; i++)