Fix #617: Incorrect C# translation when `callvirt` is used to invoke base constructor

ICSharpCode.Decompiler.Tests/TestCases/ILPretty/FSharpLoops_Debug.cs

@@ -36,11 +36,6 @@ public static class Program
 	[CompilationMapping(SourceConstructFlags.Closure)]
 	internal sealed class disposable_00403 : IDisposable
 	{
-		public disposable_00403()
-		{
-			((object)this)._002Ector();
-		}
-
 		private void System_002DIDisposable_002DDispose()
 		{
 		}

ICSharpCode.Decompiler.Tests/TestCases/ILPretty/FSharpLoops_Release.cs

@@ -37,11 +37,6 @@ public static class Program
 	[CompilationMapping(SourceConstructFlags.Closure)]
 	internal sealed class disposable_00403 : IDisposable
 	{
-		public disposable_00403()
-		{
-			((object)this)._002Ector();
-		}
-
 		private void System_002DIDisposable_002DDispose()
 		{
 		}

ICSharpCode.Decompiler/CSharp/CallBuilder.cs

@@ -187,7 +187,7 @@ namespace ICSharpCode.Decompiler.CSharp
 			} else {
 				target = expressionBuilder.TranslateTarget(
 					callArguments.FirstOrDefault(),
-					nonVirtualInvocation: callOpCode == OpCode.Call,
+					nonVirtualInvocation: callOpCode == OpCode.Call || method.IsConstructor,
 					memberStatic: method.IsStatic,
 					memberDeclaringType: constrainedTo ?? method.DeclaringType);
 				if (constrainedTo == null