fix copy paste fail in common.string

dune/stuff/test/common_string.cc

@@ -50,7 +50,7 @@ TEST(StringTest, Tokenizer)
   const vector<string> tokens_compressed = {"a", "t", "kk", "g"};
   EXPECT_EQ(tokens_default, tokenize(msg, seps, boost::algorithm::token_compress_off));
   EXPECT_EQ(tokens_compressed, tokenize(msg, seps, boost::algorithm::token_compress_on));
-#if // HAS_LAMBDA_FUNCTIONS && HAS_STD_BEGIN_END
+#if HAS_LAMBDA_FUNCTIONS && HAS_STD_BEGIN_END
   const string num_msg("-1 2;;4");
   vector<int> numbers_default    = {-1, 2, 0, 4};
   vector<int> numbers_compressed = {-1, 2, 4};