Fix crash in SwitchDetection.

ICSharpCode.Decompiler/IL/ControlFlow/SwitchDetection.cs

@@ -65,11 +65,12 @@ namespace ICSharpCode.Decompiler.IL.ControlFlow
 						Body = section.Value
 					});
 				}
-				if (block.Instructions.Last() is Branch) {
+				if (block.Instructions.Last() is SwitchInstruction) {
+					// we'll replace the switch
+				} else {
 					Debug.Assert(block.Instructions.SecondToLastOrDefault() is IfInstruction);
+					// Remove branch/leave after if; it's getting moved into a section.
 					block.Instructions.RemoveAt(block.Instructions.Count - 1);
-				} else {
-					Debug.Assert(block.Instructions.Last() is SwitchInstruction);
 				}
 				block.Instructions[block.Instructions.Count - 1] = sw;