MDEV-5800 InnoDB support for indexed vcols

  * remove old 5.2+ InnoDB support for virtual columns
  * enable corresponding parts of the innodb-5.7 sources
  * copy corresponding test cases from 5.7
  * copy detailed Alter_inplace_info::HA_ALTER_FLAGS flags from 5.7
     - and more detailed detection of changes in fill_alter_inplace_info()
  * more "innodb compatibility hooks" in sql_class.cc to
     - create/destroy/reset a THD (used by background purge threads)
     - find a prelocked table by name
     - open a table (from a background purge thread)

  * different from 5.7:
    - new service thread "thd_destructor_proxy" to make sure all THDs are
      destroyed at the correct point in time during the server shutdown
    - proper opening/closing of tables for vcol evaluations in
       + FK checks (use already opened prelocked tables)
       + purge threads (open the table, MDLock it, add it to tdc, close
         when not needed)
    - cache open tables in vc_templ
    - avoid unnecessary allocations, reuse table->record[0] and table->s->default_values
    - not needed in 5.7, because it overcalculates:
      + tell the server to calculate vcols for an on-going inline ADD INDEX
      + calculate vcols for correct error messages

  * update other engines (mroonga/tokudb) accordingly

mysql-test/include/have_innodb.combinations

@@ -9,9 +9,13 @@ innodb-locks
 innodb-buffer-pool-stats
 innodb-buffer-page
 innodb-buffer-page-lru
+innodb-sys-columns
+innodb-sys-fields
 innodb-sys-foreign
 innodb-sys-foreign-cols
+innodb-sys-indexes
 innodb-sys-tables
+innodb-sys-virtual
 innodb-metrics
 
 [xtradb_plugin]
@@ -54,6 +58,10 @@ innodb-metrics
 innodb-buffer-pool-stats
 innodb-buffer-page
 innodb-buffer-page-lru
+innodb-sys-columns
+innodb-sys-fields
 innodb-sys-foreign
 innodb-sys-foreign-cols
+innodb-sys-indexes
 innodb-sys-tables
+innodb-sys-virtual

mysql-test/suite/gcol/inc/gcol_column_def_options.inc

@@ -395,7 +395,7 @@ ALTER TABLE t CHANGE c c varchar(10) as ('a');
 ALTER TABLE t CHANGE dd d varchar(10);
 if ($support_virtual_index)
 {
-
+# no RENAME INDEX yet
 #ALTER TABLE t ADD INDEX idx(a), ADD INDEX idx1(c);
 #ALTER TABLE t RENAME INDEX idx TO idx2, RENAME INDEX idx1 TO idx3;
 #ALTER TABLE t DROP INDEX idx2, DROP INDEX idx3;

mysql-test/suite/gcol/inc/innodb_v_large_col.inc

@@ -0,0 +1,53 @@
+--source include/have_innodb.inc
+
+eval CREATE TABLE `t` (
+`a` VARCHAR(10000),   `b` VARCHAR(3000),
+`c` VARCHAR(14000) GENERATED ALWAYS AS (CONCAT(a,b)) VIRTUAL,
+`d` VARCHAR(5000) GENERATED ALWAYS AS (b) VIRTUAL,
+`e` INT(11) GENERATED ALWAYS AS (10) VIRTUAL,
+`h` INT(11) NOT NULL,
+PRIMARY KEY (`h`) ) ROW_FORMAT=$row_format  ENGINE=InnoDB;
+
+SHOW CREATE TABLE t;
+
+INSERT INTO t VALUES (REPEAT('g', 10000), REPEAT('x', 2800), DEFAULT, DEFAULT, DEFAULT, 1);
+
+INSERT INTO t VALUES (REPEAT('a', 9000), REPEAT('b', 2000), DEFAULT, DEFAULT, DEFAULT, 2);
+INSERT INTO t VALUES (REPEAT('m', 8000), REPEAT('n', 3000), DEFAULT, DEFAULT, DEFAULT, 3);
+CREATE INDEX idx ON t(c(100), d(20));
+UPDATE t SET a = REPEAT(CAST(1 AS CHAR), 2000) WHERE h = 1;
+
+delimiter |;
+CREATE PROCEDURE UPDATE_t()
+begin
+        DECLARE i INT DEFAULT 1;
+        WHILE (i <= 100) DO
+                UPDATE t SET a = REPEAT(CAST(i AS CHAR), 2000) WHERE h = 1;
+                SET i = i + 1;
+        END WHILE;
+END|
+
+CREATE PROCEDURE DELETE_insert_t()
+begin
+        DECLARE i INT DEFAULT 1;
+        WHILE (i <= 100) DO
+                DELETE FROM t WHERE h = 1;
+                INSERT INTO t VALUES (REPEAT(CAST(i AS CHAR), 2000) ,  REPEAT('b', 2000), DEFAULT, DEFAULT, DEFAULT, 1);
+                SET i = i + 1;
+        END WHILE;
+END|
+delimiter ;|
+
+CALL UPDATE_t();
+
+CALL DELETE_insert_t();
+
+UPDATE t SET a = NULL WHERE h=1;
+
+START TRANSACTION;
+CALL UPDATE_t();
+ROLLBACK;
+
+DROP PROCEDURE DELETE_insert_t;
+DROP PROCEDURE UPDATE_t;
+DROP TABLE t;