My latest fixes to gram.y cause CREATE TABLE t (f1 bool default 1 < 2)

to be accepted, but constraints regress test was expecting it to fail.

src/test/regress/input/constraints.source

@@ -40,9 +40,9 @@ CREATE TABLE error_tbl (i int DEFAULT (100, ));
 --  this will fail because gram.y uses b_expr not a_expr for defaults,
 --  to avoid a shift/reduce conflict that arises from NOT NULL being
 --  part of the column definition syntax:
-CREATE TABLE error_tbl (b1 bool DEFAULT 1 < 2);
+CREATE TABLE error_tbl (b1 bool DEFAULT 1 IN (1, 2));
 --  this should work, however:
-CREATE TABLE error_tbl (b1 bool DEFAULT (1 < 2));
+CREATE TABLE error_tbl (b1 bool DEFAULT (1 IN (1, 2)));
 
 DROP TABLE error_tbl;
 

src/test/regress/output/constraints.source

@@ -33,9 +33,9 @@ four| i1|i2
 
 QUERY: CREATE TABLE error_tbl (i int DEFAULT (100, ));
 ERROR:  parser: parse error at or near ","
-QUERY: CREATE TABLE error_tbl (b1 bool DEFAULT 1 < 2);
-ERROR:  parser: parse error at or near "<"
-QUERY: CREATE TABLE error_tbl (b1 bool DEFAULT (1 < 2));
+QUERY: CREATE TABLE error_tbl (b1 bool DEFAULT 1 IN (1, 2));
+ERROR:  parser: parse error at or near "in"
+QUERY: CREATE TABLE error_tbl (b1 bool DEFAULT (1 IN (1, 2)));
 QUERY: DROP TABLE error_tbl;
 QUERY: CREATE TABLE CHECK_TBL (x int,
 	CONSTRAINT CHECK_CON CHECK (x > 3));