increase I_S.FILES.FILE_NANE column length

because InnoDB 5.7 tdecided to store a full path there

mysql-test/suite/funcs_1/r/is_columns_is_embedded.result

@@ -128,7 +128,7 @@ def	information_schema	FILES	ENGINE	10		NO	varchar	64	192	NULL	NULL	NULL	utf8	ut
 def	information_schema	FILES	EXTENT_SIZE	16	0	NO	bigint	NULL	NULL	19	0	NULL	NULL	NULL	bigint(4)				
 def	information_schema	FILES	EXTRA	38	NULL	YES	varchar	255	765	NULL	NULL	NULL	utf8	utf8_general_ci	varchar(255)				
 def	information_schema	FILES	FILE_ID	1	0	NO	bigint	NULL	NULL	19	0	NULL	NULL	NULL	bigint(4)				
-def	information_schema	FILES	FILE_NAME	2	NULL	YES	varchar	64	192	NULL	NULL	NULL	utf8	utf8_general_ci	varchar(64)				
+def	information_schema	FILES	FILE_NAME	2	NULL	YES	varchar	512	1536	NULL	NULL	NULL	utf8	utf8_general_ci	varchar(512)				
 def	information_schema	FILES	FILE_TYPE	3		NO	varchar	20	60	NULL	NULL	NULL	utf8	utf8_general_ci	varchar(20)				
 def	information_schema	FILES	FREE_EXTENTS	14	NULL	YES	bigint	NULL	NULL	19	0	NULL	NULL	NULL	bigint(4)				
 def	information_schema	FILES	FULLTEXT_KEYS	11	NULL	YES	varchar	64	192	NULL	NULL	NULL	utf8	utf8_general_ci	varchar(64)				
@@ -644,7 +644,7 @@ NULL	information_schema	EVENTS	ORIGINATOR	bigint	NULL	NULL	NULL	NULL	bigint(10)
 3.0000	information_schema	EVENTS	COLLATION_CONNECTION	varchar	32	96	utf8	utf8_general_ci	varchar(32)
 3.0000	information_schema	EVENTS	DATABASE_COLLATION	varchar	32	96	utf8	utf8_general_ci	varchar(32)
 NULL	information_schema	FILES	FILE_ID	bigint	NULL	NULL	NULL	NULL	bigint(4)
-3.0000	information_schema	FILES	FILE_NAME	varchar	64	192	utf8	utf8_general_ci	varchar(64)
+3.0000	information_schema	FILES	FILE_NAME	varchar	512	1536	utf8	utf8_general_ci	varchar(512)
 3.0000	information_schema	FILES	FILE_TYPE	varchar	20	60	utf8	utf8_general_ci	varchar(20)
 3.0000	information_schema	FILES	TABLESPACE_NAME	varchar	64	192	utf8	utf8_general_ci	varchar(64)
 3.0000	information_schema	FILES	TABLE_CATALOG	varchar	64	192	utf8	utf8_general_ci	varchar(64)

sql/sql_show.cc

@@ -8875,7 +8875,7 @@ ST_FIELD_INFO plugin_fields_info[]=
 ST_FIELD_INFO files_fields_info[]=
 {
   {"FILE_ID", 4, MYSQL_TYPE_LONGLONG, 0, 0, 0, SKIP_OPEN_TABLE},
-  {"FILE_NAME", NAME_CHAR_LEN, MYSQL_TYPE_STRING, 0, 1, 0, SKIP_OPEN_TABLE},
+  {"FILE_NAME", FN_REFLEN, MYSQL_TYPE_STRING, 0, 1, 0, SKIP_OPEN_TABLE},
   {"FILE_TYPE", 20, MYSQL_TYPE_STRING, 0, 0, 0, SKIP_OPEN_TABLE},
   {"TABLESPACE_NAME", NAME_CHAR_LEN, MYSQL_TYPE_STRING, 0, 1, 0,
    SKIP_OPEN_TABLE},