PR #1127 and PR #1150

PR#1127: Fix is_check_constraints.result to be compatibile with 10.3

The patch is done according to the original patch for MDEV-14474
1edd09c325 and not one which is merged on server
d526679efd.
This patch includes:
- Rename from `is_check_constraint` to `is_check_constraints` to tests
and results
- Per review, change the order of fields in IS check_constraints table by adding
the column `table_name` before `constraint_name`. According to the standard
2006 there is no `table_name` column.
- Original patch and one in `10.3` supports embedded server this patch doesn't
support. After the merge `10.3` will not support also.
- Don't use patch c8b8b01b61 to change the length of `CHECK_CLAUSE` field

PR#1150: MDEV-18440: Information_schema.check_constraints possible data leak

This patch is extension of PR 1127 and includes:
- Check for table grants
- Additional test according to the MDEV specification

mysql-test/suite/funcs_1/t/is_check_constraints.test

@@ -0,0 +1,117 @@
+--source include/have_innodb.inc
+--source include/not_embedded.inc
+--echo #
+--echo # MDEV-17323: Backport INFORMATION_SCHEMA.CHECK_CONSTRAINTS to 10.2
+--echo #
+CREATE user boo1;
+GRANT select,create,alter,drop on foo.* to boo1;
+SHOW GRANTS for boo1;
+CREATE user boo2;
+create database foo;
+# Connect with user boo1
+CONNECT(con1,localhost, boo1,, foo);
+
+SET check_constraint_checks=1;
+CREATE TABLE t0
+(
+ t int, check (t>32) # table constraint
+) ENGINE=myisam;
+--sorted_result
+SELECT * from information_schema.check_constraints;
+
+ALTER TABLE t0
+ADD CONSTRAINT CHK_t0_t CHECK(t<100);
+--sorted_result
+SELECT * from information_schema.check_constraints;
+
+ALTER TABLE t0
+DROP CONSTRAINT CHK_t0_t;
+--sorted_result
+SELECT * from information_schema.check_constraints;
+
+ALTER TABLE t0
+ADD CONSTRAINT CHECK(t<50);
+--sorted_result
+SELECT * from information_schema.check_constraints;
+
+CREATE TABLE t1
+( t int CHECK(t>2), # field constraint
+ tt int,
+ CONSTRAINT CHECK (tt > 32), CONSTRAINT CHECK (tt <50),# autogenerated names table constraints
+ CONSTRAINT CHK_tt CHECK(tt<100) # named table constraint
+) ENGINE=InnoDB;
+--sorted_result
+SELECT * from information_schema.check_constraints;
+
+ALTER TABLE t1
+DROP CONSTRAINT CHK_tt;
+--sorted_result
+SELECT * from information_schema.check_constraints;
+
+CREATE TABLE t2
+(
+name VARCHAR(30) CHECK(CHAR_LENGTH(name)>2), #field constraint
+start_date DATE,
+end_date DATE,
+CONSTRAINT CHK_dates CHECK(start_date IS NULL) #table constraint
+)ENGINE=Innodb;
+--sorted_result
+SELECT * from information_schema.check_constraints;
+
+ALTER TABLE t1
+ADD CONSTRAINT CHK_new_ CHECK(t>tt);
+--sorted_result
+SELECT * from information_schema.check_constraints;
+
+# Create table with same field and table check constraint name
+CREATE TABLE t3
+(
+a int,
+b int check (b>0), # field constraint named 'b'
+CONSTRAINT b check (b>10) # table constraint
+) ENGINE=InnoDB;
+--sorted_result
+SELECT * from information_schema.check_constraints;
+
+DISCONNECT con1;
+CONNECT(con2, localhost, boo2,, test);
+--sorted_result
+SELECT * from information_schema.check_constraints;
+
+DISCONNECT con2;
+CONNECT(con1, localhost, boo1,,foo);
+DROP TABLE t0;
+DROP TABLE t1;
+DROP TABLE t2;
+DROP TABLE t3;
+DROP DATABASE foo;
+
+DISCONNECT con1;
+--CONNECTION default
+DROP USER boo1;
+DROP USER boo2;
+
+--echo #
+--echo # MDEV-18440: Information_schema.check_constraints possible data leak
+--echo #
+
+CREATE USER foo;
+CREATE DATABASE db;
+USE db;
+CREATE TABLE t1 (a int, b int, CONSTRAINT CHECK (b > 0));
+INSERT INTO t1 VALUES (1, 2), (2, 3);
+GRANT SELECT (a) ON t1 TO foo;
+
+SHOW GRANTS FOR foo;
+--sorted_result
+SELECT * FROM information_schema.check_constraints;
+
+CONNECT(con1,localhost, foo,, db);
+SELECT a FROM t1;
+--sorted_result
+SELECT * FROM information_schema.check_constraints;
+
+--CONNECTION default
+
+DROP USER foo;
+DROP DATABASE db;