C#: Fix issue with suppress nullable warning directly on a method call.

Author: michaelnebel

csharp/extractor/Semmle.Extraction.CSharp/Entities/CallTypeExtensions.cs

@@ -9,7 +9,7 @@ internal static class CallTypeExtensions
         /// </summary>
         public static ExprKind AdjustKind(this Expression.CallType ct, ExprKind k)
         {
-            if (k == ExprKind.ADDRESS_OF)
+            if (k == ExprKind.ADDRESS_OF || k == ExprKind.SUPPRESS_NULLABLE_WARNING)
             {
                 return k;
             }

csharp/extractor/Semmle.Extraction.CSharp/Entities/Expressions/PostfixUnary.cs

@@ -21,11 +21,11 @@ private PostfixUnary(ExpressionNodeInfo info, ExprKind kind, ExpressionSyntax op
         protected override void PopulateExpression(TextWriter trapFile)
         {
             Create(Context, operand, this, 0);
-            OperatorCall(trapFile, Syntax);
 
             if ((operatorKind == ExprKind.POST_INCR || operatorKind == ExprKind.POST_DECR) &&
                 Kind == ExprKind.OPERATOR_INVOCATION)
             {
+                OperatorCall(trapFile, Syntax);
                 trapFile.mutator_invocation_mode(this, 2);
             }
         }