StatementBuilder: do not insert continue statement at end of loop, if it's already present.

ICSharpCode.Decompiler/CSharp/StatementBuilder.cs

@@ -928,7 +928,7 @@ namespace ICSharpCode.Decompiler.CSharp
 			}
 			string label;
 			if (endContainerLabels.TryGetValue(container, out label)) {
-				if (isLoop) {
+				if (isLoop && !(blockStatement.LastOrDefault() is ContinueStatement)) {
 					blockStatement.Add(new ContinueStatement());
 				}
 				blockStatement.Add(new LabelStatement { Label = label });