MWL#17: Table elimination

- fix a typo bug in has_eqref_access_candidate()
- Adjust test to remove race condition

mysql-test/r/mysql-bug41486.result:
  Adjust test to remove race condition
mysql-test/t/mysql-bug41486.test:
  Adjust test to remove race condition
sql/item.cc:
  MWL#17: Table elimination:
    fix a typo bug in has_eqref_access_candidate()

mysql-test/r/mysql-bug41486.result

@@ -3,6 +3,9 @@ SET @old_max_allowed_packet= @@global.max_allowed_packet;
 SET @@global.max_allowed_packet = 2 * 1024 * 1024 + 1024;
 CREATE TABLE t1(data LONGBLOB);
 INSERT INTO t1 SELECT REPEAT('1', 2*1024*1024);
+SELECT COUNT(*) FROM t1;
+COUNT(*)
+1
 SET @old_general_log = @@global.general_log;
 SET @@global.general_log = 0;
 SET @@global.general_log = @old_general_log;

mysql-test/t/mysql-bug41486.test

@@ -27,7 +27,8 @@ connect (con1, localhost, root,,);
 
 CREATE TABLE t1(data LONGBLOB);
 INSERT INTO t1 SELECT REPEAT('1', 2*1024*1024);
-
+# The following is to remove the race between end of insert and start of MYSQL_DUMP:
+SELECT COUNT(*) FROM t1;
 let $outfile= $MYSQLTEST_VARDIR/tmp/bug41486.sql;
 --error 0,1
 remove_file $outfile;

sql/item.cc

@@ -1935,8 +1935,9 @@ bool Item_field::check_column_usage_processor(uchar *arg)
         break;
       }
     }
+    return FALSE;
   }
-  return FALSE;
+  return TRUE;
 }
 
 const char *Item_ident::full_name() const