Fix qp_with_clause testcase without asserts (#13878)

- Fix off-by-one error in 71dd8b0239
- Add optimizer_trace_fallback to catch issue in non-assert build

src/backend/gporca/libgpopt/src/operators/CExpressionPreprocessor.cpp

@@ -2844,7 +2844,7 @@ CExpressionPreprocessor::PexprTransposeSelectAndProject(CMemoryPool *mp,
 			exprhdl.Attach(pprojexpr);
 			exprhdl.DeriveProps(nullptr /*pdpctxt*/);
 
-			if (exprhdl.Arity() > 0 && exprhdl.DeriveHasNonScalarFunction(1))
+			if (exprhdl.Arity() > 1 && exprhdl.DeriveHasNonScalarFunction(1))
 			{
 				// Bail if project expression contains a set-returning function
 				pdrgpexpr->Release();

src/test/regress/expected/qp_with_clause.out

@@ -16,6 +16,7 @@ NOTICE:  table "country" does not exist, skipping
 DROP TABLE IF EXISTS countrylanguage cascade;
 NOTICE:  table "countrylanguage" does not exist, skipping
 --end_ignore
+SET optimizer_trace_fallback=on;
 BEGIN;
 --SET client_encoding = 'LATIN1';
 CREATE TABLE city (
@@ -614,6 +615,7 @@ where e1.code = e2.code order by e2.COUNTRY,e1.language LIMIT 20;
  GIB  | Gibraltar              | Gibraltar              | English        | t          |       88.9 | GIB  | Gibraltar              | Gibraltar              | English        | t          |       88.9
 (20 rows)
 
+SET optimizer_trace_fallback=off;
 -- query 2 using multiple CTEs with same names as tables. 
 with country as 
 (select country.code,country.name COUNTRY, city.name CAPITAL, language, isofficial, percentage
@@ -655,6 +657,7 @@ order by COUNTRY,percentage1 LIMIT 20;-- queries using same name for CTEs and th
  GIB   | Gibraltar              | Gibraltar              | English        | t           |        88.9 | Gibraltar
 (20 rows)
 
+SET optimizer_trace_fallback=on;
 -- query1
 with c1 as 
 (select country.code,country.name COUNTRY, city.name CAPITAL, language, isofficial, percentage
@@ -11129,3 +11132,4 @@ NOTICE:  drop cascades to table countrylanguage
 NOTICE:  drop cascades to table country
 NOTICE:  drop cascades to table city
 -- end_ignore
+RESET optimizer_trace_fallback;