MDEV-7563 Support CHECK constraint as in (or close to) SQL Standard

MDEV-10134 Add full support for DEFAULT

- Added support for using tables with MySQL 5.7 virtual fields,
  including MySQL 5.7 syntax
- Better error messages also for old cases
- CREATE ... SELECT now also updates timestamp columns
- Blob can now have default values
- Added new system variable "check_constraint_checks", to turn of
  CHECK constraint checking if needed.
- Removed some engine independent tests in suite vcol to only test myisam
- Moved some tests from 'include' to 't'. Should some day be done for all tests.
- FRM version increased to 11 if one uses virtual fields or constraints
- Changed to use a bitmap to check if a field has got a value, instead of
  setting HAS_EXPLICIT_VALUE bit in field flags
- Expressions can now be up to 65K in total
- Ensure we are not refering to uninitialized fields when handling virtual fields or defaults
- Changed check_vcol_func_processor() to return a bitmap of used types
- Had to change some functions that calculated cached value in fix_fields to do
  this in val() or getdate() instead.
- store_now_in_TIME() now takes a THD argument
- fill_record() now updates default values
- Add a lookahead for NOT NULL, to be able to handle DEFAULT 1+1 NOT NULL
- Automatically generate a name for constraints that doesn't have a name
- Added support for ALTER TABLE DROP CONSTRAINT
- Ensure that partition functions register virtual fields used. This fixes
  some bugs when using virtual fields in a partitioning function

mysql-test/suite/rpl/t/rpl_default.test

@@ -0,0 +1,29 @@
+#
+# Test of replicating default values
+# As the table is using non deterministic functions, replication must
+# switch to binlog format.
+#
+
+-- source include/have_binlog_format_mixed_or_row.inc
+-- source include/master-slave.inc
+
+connection master;
+
+create table t1 (a int DEFAULT 1+1, b bigint default uuid_short(), u blob default user());
+insert into t1 (a) values(1);
+
+let $b=query_get_value(select * from t1, b, 1);
+let $u=query_get_value(select * from t1, u, 1); 
+
+sync_slave_with_master;
+connection slave;
+
+show create table t1;
+--disable_query_log
+eval select a,"$b"=b as uuid,"$u"=u as user from t1;
+--enable_query_log
+connection master;
+
+drop table t1;
+
+--source include/rpl_end.inc