MDEV-11429 Increase number of max table_open_cache instances

Increase max number of possible table_open_cache instances from 512K
to 1024K. This only affects user who are trying to set the variable over
the old limit.

Delete not used test table_open_cache_instances_basic
(Need to be added back and rewritten in 10.2)

mysql-test/suite/sys_vars/disabled.def

@@ -11,5 +11,4 @@
 ##############################################################################
 
 innodb_flush_checkpoint_debug_basic: removed from XtraDB-26.0
-table_open_cache_instances_basic: no such variable in MariaDB
 all_vars: obsolete, see sysvars_* tests

mysql-test/suite/sys_vars/r/sysvars_server_notembedded.result

@@ -4540,7 +4540,7 @@ VARIABLE_SCOPE	GLOBAL
 VARIABLE_TYPE	BIGINT UNSIGNED
 VARIABLE_COMMENT	The number of cached open tables
 NUMERIC_MIN_VALUE	1
-NUMERIC_MAX_VALUE	524288
+NUMERIC_MAX_VALUE	1048576
 NUMERIC_BLOCK_SIZE	1
 ENUM_VALUE_LIST	NULL
 READ_ONLY	NO

mysql-test/suite/sys_vars/r/table_open_cache_basic.result

@@ -27,7 +27,7 @@ Warnings:
 Warning	1292	Truncated incorrect table_open_cache value: '1073741824'
 SELECT @@global.table_open_cache ;
 @@global.table_open_cache
-524288
+1048576
 SET @@global.table_open_cache  = 18000;
 SELECT @@global.table_open_cache ;
 @@global.table_open_cache
@@ -48,7 +48,7 @@ Warnings:
 Warning	1292	Truncated incorrect table_open_cache value: '100000000000'
 SELECT @@global.table_open_cache ;
 @@global.table_open_cache
-524288
+1048576
 SET @@global.table_open_cache = -1024;
 Warnings:
 Warning	1292	Truncated incorrect table_open_cache value: '-1024'

mysql-test/suite/sys_vars/r/table_open_cache_instances_basic.result

-select @@table_open_cache_instances;
-@@table_open_cache_instances
-1

mysql-test/suite/sys_vars/t/table_open_cache_instances_basic.test

-select @@table_open_cache_instances;

sql/sys_vars.cc

@@ -3219,7 +3219,7 @@ static bool fix_table_open_cache(sys_var *, THD *, enum_var_type)
 static Sys_var_ulong Sys_table_cache_size(
        "table_open_cache", "The number of cached open tables",
        GLOBAL_VAR(tc_size), CMD_LINE(REQUIRED_ARG),
-       VALID_RANGE(1, 512*1024), DEFAULT(TABLE_OPEN_CACHE_DEFAULT),
+       VALID_RANGE(1, 1024*1024), DEFAULT(TABLE_OPEN_CACHE_DEFAULT),
        BLOCK_SIZE(1), NO_MUTEX_GUARD, NOT_IN_BINLOG, ON_CHECK(0),
        ON_UPDATE(fix_table_open_cache));