fix #973

TestSuite/lambdas_exceptions.pas

@@ -0,0 +1,14 @@
+begin
+  var i := 0;
+  var p: procedure := ()->try
+    raise new Exception('test');
+  except 
+    on ex: Exception do
+    begin
+      i := 1;
+    end;
+      
+  end;
+  p;
+  assert(i = 1);
+end.

TreeConverter/LambdaExpressions/Closure/CapturedVariablesTreeBuilder.cs

@@ -129,6 +129,11 @@ namespace TreeConverter.LambdaExpressions.Closure
             }
         }
 
+        public override void visit(exception_handler _exception_handler)
+        {
+            ProcessNode(_exception_handler.statements);
+        }
+
         public override void visit(ident id)
         {
             var idName = id.name.ToLower();