MDEV-20987 InnoDB fails to start when fts table has FK relation

InnoDB: Assertion failure in file .../dict/dict0dict.cc line ...
InnoDB: Failing assertion: table->can_be_evicted

This fixes a regression that was caused by the fix of MDEV-20621
(commit a41d4297).
MySQL 5.6 (and MariaDB 10.0) introduced eviction of tables from
the InnoDB data dictionary cache. Tables that are connected to
FOREIGN KEY constraints or FULLTEXT INDEX are exempt of the eviction.
With the problematic change, a table that would already be exempt
from eviction due to FOREIGN KEY would cause the problem if there
also was a FULLTEXT INDEX defined on it.

dict_load_table(): Only prevent eviction if table->can_be_evicted holds.

mysql-test/suite/innodb_fts/r/innodb_fts_misc.result

-drop table if exists t1;
 CREATE TABLE t1 (
 id INT UNSIGNED AUTO_INCREMENT NOT NULL PRIMARY KEY,
 a VARCHAR(200),
@@ -415,7 +414,6 @@ AGAINST ('"following database"@10' IN BOOLEAN MODE);
 id
 105
 DROP TABLE t1;
-drop table if exists t50;
 set names utf8;
 "----------Test1---------"
 create table t50 (s1 varchar(60) character set utf8 collate utf8_bin) engine = innodb;
@@ -670,9 +668,6 @@ s1
 ŁŁŁŁ
 LLLL
 ŁŁŁŁ ŁŁŁŁ
-DROP TABLE if EXISTS t2;
-Warnings:
-Note	1051	Unknown table 'test.t2'
 CREATE TABLE t2 (s1 VARCHAR(60) CHARACTER SET UTF8 COLLATE UTF8_POLISH_CI) ENGINE = InnoDB;
 CREATE FULLTEXT INDEX i ON t2 ( s1);
 Warnings:
@@ -739,7 +734,12 @@ ALTER TABLE t2 DROP a;
 SET @@autocommit=0;
 CREATE FULLTEXT INDEX i ON t1 (char_column);
 INSERT INTO t1 values (1,'aaa');
-"restart server..."
+CREATE TABLE mdev20987_1(f1 INT NOT NULL, PRIMARY KEY(f1))ENGINE=InnoDB;
+CREATE TABLE mdev20987_2(f1 INT NOT NULL, f2 CHAR(100),
+FULLTEXT(f2),
+FOREIGN KEY(f1) REFERENCES mdev20987_1(f1))ENGINE=InnoDB;
+INSERT INTO mdev20987_1 VALUES(1);
+INSERT INTO mdev20987_2 VALUES(1, 'mariadb');
 SHOW CREATE TABLE t2;
 Table	Create Table
 t2	CREATE TABLE `t2` (
@@ -747,12 +747,8 @@ t2	CREATE TABLE `t2` (
   PRIMARY KEY (`FTS_DOC_ID`)
 ) ENGINE=InnoDB DEFAULT CHARSET=latin1
 DELETE FROM t1 WHERE MATCH(char_column) AGAINST ('bbb');
-SET @@autocommit=1;
-DROP TABLE t1, t2;
+DROP TABLE t1, t2, mdev20987_2, mdev20987_1;
 "----------Test28---------"
-drop table if exists `fts_test`;
-Warnings:
-Note	1051	Unknown table 'test.fts_test'
 create table `fts_test`(`a` text,fulltext key(`a`))engine=innodb;
 set session autocommit=0;
 insert into `fts_test` values ('');
@@ -942,9 +938,6 @@ id	title	body
 2	How To Use MySQL Well	After you went through a ...
 3	Optimizing MySQL	In this tutorial we will show ...
 DROP TABLE articles;
-drop table if exists t1;
-Warnings:
-Note	1051	Unknown table 'test.t1'
 create table t1 (FTS_DOC_ID bigint unsigned auto_increment not null primary key,
 title varchar(200),body text,fulltext(title,body)) engine=innodb;
 insert into t1 set body='test';

mysql-test/suite/innodb_fts/t/innodb_fts_misc.test

@@ -5,10 +5,6 @@
 let collation=UTF8_UNICODE_CI;
 --source include/have_collation.inc
 
---disable_warnings
-drop table if exists t1;
---enable_warnings
-
 # Create FTS table
 CREATE TABLE t1 (
         id INT UNSIGNED AUTO_INCREMENT NOT NULL PRIMARY KEY,
@@ -401,10 +397,6 @@ DROP TABLE t1;
 #------------------------------------------------------------------------------
 # More FTS test from peter's testing
 #------------------------------------------------------------------------------
---disable_warnings
-drop table if exists t50;
---enable_warnings
-
 set names utf8;
 
 
@@ -606,7 +598,6 @@ CREATE FULLTEXT INDEX i ON t1 (s1);
 INSERT INTO t1 VALUES
 ('a'),('b'),('c'),('d'),('ŁŁŁŁ'),('LLLL'),(NULL),('ŁŁŁŁ ŁŁŁŁ'),('LLLLLLLL');
 SELECT * FROM t1 WHERE MATCH(s1) AGAINST ('LLLL' COLLATE UTF8_UNICODE_520_CI);
-DROP TABLE if EXISTS t2;
 CREATE TABLE t2 (s1 VARCHAR(60) CHARACTER SET UTF8 COLLATE UTF8_POLISH_CI) ENGINE = InnoDB;
 CREATE FULLTEXT INDEX i ON t2 ( s1);
 INSERT INTO t2 VALUES
@@ -672,16 +663,19 @@ ALTER TABLE t2 DROP a;
 SET @@autocommit=0;
 CREATE FULLTEXT INDEX i ON t1 (char_column);
 INSERT INTO t1 values (1,'aaa');
-echo "restart server...";
-# Restart the server
+
+CREATE TABLE mdev20987_1(f1 INT NOT NULL, PRIMARY KEY(f1))ENGINE=InnoDB;
+CREATE TABLE mdev20987_2(f1 INT NOT NULL, f2 CHAR(100),
+                FULLTEXT(f2),
+                FOREIGN KEY(f1) REFERENCES mdev20987_1(f1))ENGINE=InnoDB;
+INSERT INTO mdev20987_1 VALUES(1);
+INSERT INTO mdev20987_2 VALUES(1, 'mariadb');
 --source include/restart_mysqld.inc
 SHOW CREATE TABLE t2;
 DELETE FROM t1 WHERE MATCH(char_column) AGAINST ('bbb');
-SET @@autocommit=1;
-DROP TABLE t1, t2;
+DROP TABLE t1, t2, mdev20987_2, mdev20987_1;
 
 --echo "----------Test28---------"
-drop table if exists `fts_test`;
 create table `fts_test`(`a` text,fulltext key(`a`))engine=innodb;
 set session autocommit=0;
 insert into `fts_test` values ('');
@@ -870,8 +864,6 @@ DROP TABLE articles;
 # Test for Bug 13940669 - 64901: INNODB: ASSERTION FAILURE IN
 # THREAD 34387022112 IN FILE REM0CMP.CC LINE 5
 
-drop table if exists t1;
-
 create table t1 (FTS_DOC_ID bigint unsigned auto_increment not null primary key,
 title varchar(200),body text,fulltext(title,body)) engine=innodb;
 

storage/innobase/dict/dict0load.cc

@@ -2551,7 +2551,7 @@ dict_load_table(
 			fts_free(table);
 		} else if (fts_optimize_wq) {
 			fts_optimize_add_table(table);
-		} else {
+		} else if (table->can_be_evicted) {
 			/* fts_optimize_thread is not started yet.
 			So make the table as non-evictable from cache. */
 			dict_table_move_from_lru_to_non_lru(table);

storage/xtradb/dict/dict0load.cc

@@ -2573,7 +2573,7 @@ dict_load_table(
 			fts_free(table);
 		} else if (fts_optimize_wq) {
 			fts_optimize_add_table(table);
-		} else {
+		} else if (table->can_be_evicted) {
 			/* fts_optimize_thread is not started yet.
 			So make the table as non-evictable from cache. */
 			dict_table_move_from_lru_to_non_lru(table);