[no-release-notes] info schema set as main db panic test (#2873)

* [no-release-notes] info schema set as main db panic test

* edit query a bit

Author: max-hoffman

enginetest/queries/information_schema_queries.go

@@ -874,6 +874,18 @@ var InfoSchemaScripts = []ScriptTest{
 			},
 		},
 	},
+	{
+		Name: "issue 8930: connect to info schema",
+		SetUpScript: []string{
+			"use information_schema",
+		},
+		Assertions: []ScriptTestAssertion{
+			{
+				Query:    "SELECT C.COLUMN_NAME AS label, 'connection.column' as \"type\", C.TABLE_NAME AS \"table\", C.DATA_TYPE AS \"dataType\", CAST(C.CHARACTER_MAXIMUM_LENGTH AS UNSIGNED) AS size, CAST(UPPER( CONCAT( C.DATA_TYPE, CASE WHEN C.DATA_TYPE = 'text' THEN '' ELSE ( CASE WHEN C.CHARACTER_MAXIMUM_LENGTH > 0 THEN ( CONCAT('(', C.CHARACTER_MAXIMUM_LENGTH, ')') ) ELSE '' END ) END ) ) AS CHAR CHARACTER SET utf8) AS \"detail\", C.TABLE_CATALOG AS \"catalog\", C.TABLE_SCHEMA AS \"database\", C.TABLE_SCHEMA AS \"schema\", C.COLUMN_DEFAULT AS \"defaultValue\", C.IS_NULLABLE AS \"isNullable\", (CASE WHEN C.COLUMN_KEY = 'PRI' THEN 1 ELSE 0 END) AS \"isPk\", (CASE WHEN KCU.REFERENCED_COLUMN_NAME IS NULL THEN 0 ELSE 1 END) AS \"isFk\" FROM INFORMATION_SCHEMA.COLUMNS AS C LEFT JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE AS KCU ON ( C.TABLE_NAME = KCU.TABLE_NAME AND C.TABLE_SCHEMA = KCU.TABLE_SCHEMA AND C.TABLE_CATALOG = KCU.TABLE_CATALOG AND C.COLUMN_NAME = KCU.COLUMN_NAME ) JOIN INFORMATION_SCHEMA.TABLES AS T ON C.TABLE_NAME = T.TABLE_NAME AND C.TABLE_SCHEMA = T.TABLE_SCHEMA AND C.TABLE_CATALOG = T.TABLE_CATALOG WHERE C.TABLE_SCHEMA = 'dev' AND C.TABLE_NAME = 'countries' AND C.TABLE_CATALOG = 'def' ORDER BY C.TABLE_NAME, C.ORDINAL_POSITION",
+				Expected: []sql.Row{},
+			},
+		},
+	},
 	{
 		Name: "query does not use optimization rule on LIKE clause because info_schema db charset is utf8mb3",
 		SetUpScript: []string{