parse_coerce fix allows early simplification of one

constant-coercion expression in the rules test.

src/test/regress/expected/rules.out

@@ -1092,7 +1092,7 @@ toyemp            |SELECT "name", "age", "location", '12'::"int4" * "salary" AS
 QUERY: SELECT tablename, rulename, definition FROM pg_rules
 	ORDER BY tablename, rulename;
 tablename    |rulename       |definition                                                                                                                                                                                                                                                        
--------------+---------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+-------------+---------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 rtest_emp    |rtest_emp_del  |CREATE RULE "rtest_emp_del" AS ON DELETE TO "rtest_emp" DO INSERT INTO "rtest_emplog" ("ename", "who", "action", "newsal", "oldsal") VALUES (old."ename", "getpgusername"(), 'fired'::"bpchar", '$0.00'::"money", old."salary");                                  
 rtest_emp    |rtest_emp_ins  |CREATE RULE "rtest_emp_ins" AS ON INSERT TO "rtest_emp" DO INSERT INTO "rtest_emplog" ("ename", "who", "action", "newsal", "oldsal") VALUES (new."ename", "getpgusername"(), 'hired'::"bpchar", new."salary", '$0.00'::"money");                                  
 rtest_emp    |rtest_emp_upd  |CREATE RULE "rtest_emp_upd" AS ON UPDATE TO "rtest_emp" WHERE new."salary" <> old."salary" DO INSERT INTO "rtest_emplog" ("ename", "who", "action", "newsal", "oldsal") VALUES (new."ename", "getpgusername"(), 'honored'::"bpchar", new."salary", old."salary"); 
@@ -1118,7 +1118,7 @@ rtest_v1     |rtest_v1_upd   |CREATE RULE "rtest_v1_upd" AS ON UPDATE TO "rtest_
 shoelace     |shoelace_del   |CREATE RULE "shoelace_del" AS ON DELETE TO "shoelace" DO INSTEAD DELETE FROM "shoelace_data" WHERE "sl_name" = old."sl_name";                                                                                                                                     
 shoelace     |shoelace_ins   |CREATE RULE "shoelace_ins" AS ON INSERT TO "shoelace" DO INSTEAD INSERT INTO "shoelace_data" ("sl_name", "sl_avail", "sl_color", "sl_len", "sl_unit") VALUES (new."sl_name", new."sl_avail", new."sl_color", new."sl_len", new."sl_unit");                        
 shoelace     |shoelace_upd   |CREATE RULE "shoelace_upd" AS ON UPDATE TO "shoelace" DO INSTEAD UPDATE shoelace_data SET "sl_name" = new."sl_name", "sl_avail" = new."sl_avail", "sl_color" = new."sl_color", "sl_len" = new."sl_len", "sl_unit" = new."sl_unit" WHERE "sl_name" = old."sl_name";
-shoelace_data|log_shoelace   |CREATE RULE "log_shoelace" AS ON UPDATE TO "shoelace_data" WHERE new."sl_avail" <> old."sl_avail" DO INSERT INTO "shoelace_log" ("sl_name", "sl_avail", "log_who", "log_when") VALUES (new."sl_name", new."sl_avail", 'Al Bundy'::"name", "datetime"('epoch'::"text"));
+shoelace_data|log_shoelace   |CREATE RULE "log_shoelace" AS ON UPDATE TO "shoelace_data" WHERE new."sl_avail" <> old."sl_avail" DO INSERT INTO "shoelace_log" ("sl_name", "sl_avail", "log_who", "log_when") VALUES (new."sl_name", new."sl_avail", 'Al Bundy'::"name", 'epoch'::"datetime");   
 shoelace_ok  |shoelace_ok_ins|CREATE RULE "shoelace_ok_ins" AS ON INSERT TO "shoelace_ok" DO INSTEAD UPDATE shoelace SET "sl_avail" = "sl_avail" + new."ok_quant" WHERE "sl_name" = new."ok_name";                                                                                              
 (27 rows)